Hillside of left bank of dam site is covered by higher terrace deposit.

Transcription

1 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter Geology of Dam Site C The geology of Dam Site C is summarized as follows: Mesozoic granite, Proterozoic gabbro and gneiss are distributed around the dam site. These are hard and massive rocks. Proterozoic gneiss is distributed at the downstream of the dam site. It is hard and massive rock. Some small caves are found at the left bank at downstream of dam site, where the crystalline limestone is distributed. Hillside of left bank of dam site is covered by higher terrace deposit. Unconsolidated sediment, which consists of middle terrace deposit, lower terrace deposit, talus deposit and riverbed deposit, is distributed along river. Two small faults named CF-1 and CF-2 are observed at the left bank (Figure 4.3.9). CF-1 is a small fault accompanied with altered zone 50~80cm wide. Dip and strike of fault plane of CF-1 is 70N and N75W respectively. CF-2 is a very small fault which has fault clay zone of 1~2mm wide and crashed zone of 10cm wide. Dip and strike of fault plane of CF-2 is 85S and N85E respectively. There is a landslide named LS-L1 at the left bank of upstream of dam site. Since LS-L1 is small and distribution area of LS-L1 is limited within the reservoir area, LS-L1 will not cause a serious problem. Figure Geologic Map around Dam Site C CTI Engineering International Co., Ltd. and 4-33

2 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Figure Geologic Profile along Dam Axis C and Salang River 4-34 CTI Engineering International Co., Ltd. and

3 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Upstream View of Damsite C Granite Outcrop intruded by Pegmatite Vein at the Riverbed Intrusive plane is closed. Black colored minerals are tourmaline. Small caves are formed by dissolution of crystalline limestone by rain at left bank of downstream of Dam Site C. [Left] CF-1Fault - Location: excavated slope of road at about 30m downstream of dam axis - Dip and strike: 70N and N75W - Width of altered zone: 50-80cm Figure Upstream View of Dam Site C and Outcrop of Granite with Pegmatite Intrusive, Cave of Crystalline Limestone Distant View of Right Bank of Dam Site CTI Engineering International Co., Ltd. and 4-35

4 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Geology of Dam Site D The geology of Dam Site D is summarized as follows: Mesozoic granite is distributed around Dam Site D. It is hard and massive rock. Proterozoic gneiss is distributed at the downstream and upstream of dam site. It is hard and massive rock. Unconsolidated sediment, which consists of middle terrace deposit, lower terrace deposit, talus deposit and riverbed deposit, is distributed along river. Two small faults named DF-1 and DF-2 are observed around the dam axis (Figure ). DF-1 is a small fault which has a crushed zone of 30cm wide. Dip and strike of fault plane of DF-1 is 60S and N70E respectively. DF-2 is very small fault which has a crashed zone of 5cm wide. Dip and strike of fault plane of DF-2 is 65N and N65E respectively. High angle fault striation was observed on the surface of fault plane of DF-2. There is a landslide named LS-L3 at the left bank of upstream of dam site. Since LS-L3 is small and most of the distribution area of LS-L3 is limited within the reservoir area, LS-L3 will not cause a serious problem. There is a relatively large landslide named LS-R2 in the right bank of reservoir area, as mentioned in Detail survey of land slide is necessary in case Dam Site D is selected as the optimum dam site. Figure Geologic Map around Dam Site D 4-36 CTI Engineering International Co., Ltd. and

5 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Figure Geologic Profile along Dam Axis D and Salang River CTI Engineering International Co., Ltd. and 4-37

6 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Upstream View of Dam Site D Outcrop of Granite at Excavate Slope of Road of Dam Axis Outcrop of Granite containing Mafic Xenolith Outcrop of DF-2 at Left Bank Downstream of Dam Axis - DF-2 is very small fault which has crashed zone of 5cm wide. - Dip and strike of fault plane of DF-2 is 65N and N65E. - High angle fault striation was observed on the surface of fault plane of DF-2. Outcrop of DF-1 at Right Bank of River Bed - DF-1 is small fault which has crushed zone of 30cm wide. - Dip and strike of fault plane of DF-1 is 60S and N70E. Figure Upstream View of Dam Site D and Outcrop of Granite Containing Mafic Inclusion, DF-1 and DF CTI Engineering International Co., Ltd. and

7 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter Geology of Dam Site E The geology of Dam Site E is summarized as follows: Mesozoic schist is distributed around Dam Site E. It is hard and massive rock. Unconsolidated sediment, which consists of middle terrace deposit, lower terrace deposit, talus deposit and river bed deposit, id distributed along river. One small fault named EF-1 is observed around the dam axis (Figure ). EF-1 is a very small fault which has a crushed zone of 20cm wide. Dip and strike of fault plane of EF-1 is 48N and N70E respectively. There are two landslides named LS-L3 and LS-R4 in the reservoir area. Since LS-L3 and LS-R4 are small and distribution area of LS-R3 is limited within the reservoir area, they will not cause a serious problem. Figure Geologic Map around Dam Site E R3 CTI Engineering International Co., Ltd. and 4-39

8 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Figure Geologic Profile along Dam Axis E and Salang River 4-40 CTI Engineering International Co., Ltd. and

9 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Downstream View of Dam Site E Axis of Dam Psamitic Schist crops out on excavated slope of road. Thin middle terrace deposit is observed at the left of photograph. Upstream View of Dam Site E Quartzite EF-1 Outcrop of Quartzite Interbedded in Psamitic Schist Figure Outcrop of EF-1 Fault - EF-1 is very small fault which has crushed zone of 20cm wide. - Dip and strike of fault plane of EF-1 is 48N and N70E. Downstream View of Dam Site E and Outcrop of Psamitic Schist Containing Interbedded Quartzite, EF-1 Fault CTI Engineering International Co., Ltd. and 4-41

10 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for 4.4 Results of Geo-Technical Survey Description of Geo-Technical Survey The geotechnical survey was intended to provide data on the nature of the proposed dam site foundations available for construction of the structures. The results of this survey are to be utilized for executing the preliminary feasibility study on the construction of a multipurpose dam Purposes This geotechnical survey was carried out for the following purposes: To obtain data on site subsurface conditions through drilling. To obtain data on the permeability of dam foundations through in-situ lugeon tests. To determine the physical and mechanical properties of rock samples through laboratory tests Selection of Drilling Site and Determination of Drill Length As shown in the next section and based on the comparison of construction costs, three (3) relatively good dam sites were selected from the five (5) alternative dam sites. For each selected dam site, one (1) drilling point on the axis of dam was selected. Drill length was determined to be 100m based on the height of planned dam which is about 100m Work Quantities Work quantities are as summarized in Table Table Work Quantities No. Items Quantity Note 1 Core Drilling (Diameter: 66mm) 3 drill holes, 300m in total 2 Lugeon Test 57 times (every 5m of core drilling) Single packer method 3 Laboratory Test for Drillhole Core 25 samples In accordance with ASTM Location of the Works Locations of actual drilling sites are as shown in Figure 4.4.1, Figure and Table Name of Drill Hole Latitude Table Longitude Location of Actual Drilling Sites Coordinate: X (m) Coordinate: Y (m) Ground Height (EL.m) Height of Concrete Mark (m) BC ' " 69 13' " , BD ' " 69 12' " , BE ' " 69 12' " , Machine Name: GPS - Leica 1200 Precision of Coordinate: ±0.24m Precision of Elevation: ±1.20m 4-42 CTI Engineering International Co., Ltd. and

11 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Location of Geotechnical Survey for Salang Dam Figure Location Map of the Project Area CTI Engineering International Co., Ltd. and 4-43

12 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Dam Site E Dam Site D Dam Site C Figure Location Map of Drilling Sites 4-44 CTI Engineering International Co., Ltd. and

13 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter Equipment and Method (1) Drilling (a) Equipment and Method The field investigation of subsurface materials included a reconnaissance of the project site, drilling of drill-holes 100 meters in depth, and performing lugeon tests (per 5 meters). The drilling consisted of 3 drill-holes [drilling angle = 90 degrees (vertical)]. Work quantities are as summarized in Table Conditions of the works are as shown in Annex _7. Table Quantities of Drilling Name of Drillhole Drilled Depth Drilling Angle Lugeon Test (quantity) BC m 90 degree (Vertical) 19 times BD m 90 degree (Vertical) 19 times BE m 90 degree (Vertical) 19 times Total 300 m - 57 times Before drilling, scaffoldings (concrete block) were built at each drilling site. The sizes of scaffoldings are as shown in Table After drilling, the scaffoldings were demolished and dismantled. Table Size of Concrete Scaffoldings Drillhole No. Width (m) Length (m) Height (m) BC BD BE Drilling was carried out using GXY-2 core drilling rig machine, core barrel 89 and 86 mm. Groundwater level in drill-holes was measured every morning before the commencement of drilling. All samples were identified according to project name, drill-hole number, depth, core recovery (CR%) and rock quality designation index (RQD%) and kept in wooden core boxes [each wooden core box has five (5) grooves, each of which contains 1 meter of core sample]. Then each drill-hole was filled with cement milk and concrete marker was built on the drilling site. (b) Rock Mass Classification For the purpose of estimating strength, bedrock was classified into six (6) classes based on the standard shown in Table The classification can be expressed as the combination of subdivisions as shown in Table Examples of combination of drill-hole cores are shown in Table Bedrock could also be classified according to the degree of weathering (Table 4.4.8) and hydrothermal alteration (Table 4.4.9). CTI Engineering International Co., Ltd. and 4-45

14 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Class A B Table Standard of Rock Mass Classifications for Dam Foundation General Description Rock mass is fresh and very hard. When struck by hammer, rock piece cannot be broken easily. Sound by hammer blow is metallic and clear. Length of drillhole core is more than 200cm. Joints and cracks are tight. Rock mass is fresh and hard. When struck by hammer, rock piece cannot be broken easily. Sound by hammer blow is metallic and clear. Length of drillhole core is about cm. Joints and cracks are tight. CH CM CL D Rock mass is fresh and hard. Sound by hammer blow is metallic. Length of drillhole core is about 15-50cm, long columnar shape. Joints and cracks are tight or partly weathered. Rock mass is fresh or weak weathered and relatively solid. When struck by hammer, rock pieces are separated along the joints. Sound by hammer blow is a little dim. Length of drillhole core is about 5-15cm, short columnar shape. Joints and cracks are partly weathered. Rock mass is weathered and soft. When struck by hammer, rock pieces are crashed easily. Sound by hammer blow is dim. Length of drillhole core is less than 5cm, gravel like core shape. Joints and cracks are weathered. Rock mass is weathered and very soft. Rock pieces are crashed easily by the weak blow of hammer. Sound by hammer blow is remarkably dim. Shape of drillhole core is sandy or clayey. No sample is contained in this class. Joints and cracks are indistinguishable. After Japan Society of Engineering Geology 1992: Rock Mass Classification in Japan Table Standards of Drill-hole Core Subdivisions Class Hardness A Very hard (σ c 100MPa) B Hard (40 σ c<100mpa) C Partly hard, partly soft. Relatively soft. D Soft E Very soft Class Drillhole Core Shape Ⅰ Length of drillhole core is more than 50cm. Very long columnar shape. Ⅱ Length of drillhole core is about 15-50cm. Long columnar shape. Ⅲ Length of drillhole core is about 5-15cm. Short columnar shape. Ⅳ Length of drillhole core is less than 5cm. Ⅴ Gravel like drillhole core shape. Ⅵ Sandy drillhole core shape. Ⅶ Clayey drillhole core shape. No sample. Class Condition of Crack a Tight. Closely adhered. b Weathered. Stained by oxidation (limonite). c Opening. Clay is sandwiched. d Original joint planes become indistinguishable. After Japan Construction Information Center 1999: Guideline for Geologic Log (Draft) 4-46 CTI Engineering International Co., Ltd. and

15 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Table Example of Combination of Subdivisions for Rockmass Classification Hardness Drill-hole Core Shape Condition of Crack a b c d Ⅰ A, B CH CH - Ⅱ CH CH CM - A Ⅲ CH CM CM - Ⅳ CM CM CL - Ⅴ CL Ⅰ CH CH CM - Ⅱ CH CM CM - B Ⅲ CM CM CL - Ⅳ CM CL CL - Ⅴ CL Ⅰ CH CM CM - Ⅱ CM CM CM - C Ⅲ CM CM CL - Ⅳ CM CL CL - Ⅴ CL Ⅲ CL CL CL - D Ⅳ CL CL CL - Ⅴ D Ⅵ D E Ⅶ D Table Standard of Weathering of Drillhole Core Class Condition of Weathering α No weathered. Rock mass is fresh and hard. Cracks are fresh or partly contaminated by limonite. β Along cracks Rock mass changed rather brittle. Cracks are contaminated by limonite. γ Weak weathered. Rock mass along the crack become discolored and brittle. Center of rock mass is fresh. δ Weathered. Rock mass become discolored and brittle. ε Hard weathered. Rock mass become clayey and soft. After Japan Construction Information Center 1999: Guideline for Geologic Log (Draft) Table Standard of Hydrothermal Alteration for Drillhole Core Class Condition of Hydrothermal Alteration 1 Not altered. No alteration minerals. Weak altered. Rock mass along the crack becomes discolored and/or stained by altered minerals. 2 Relatively solid. 3 Altered. Rock mass become discolored and relatively soft. 4 Hard altered. Rock mass become soft. Difficult to determine the original rock specie. After Japan Construction Information Center 1999: Guideline for Geologic Log (Draft) CTI Engineering International Co., Ltd. and 4-47

16 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (2) Lugeon Test (a) Equipment Equipment for the Lugeon Test is as shown in Table Table Equipment for Lugeon Test Equipment Capacity / Specification Water Pump 160 liter / min, Less Pulsation Type Flow Meter Sensitivity : 0.1 liter Pressure Gauge Sensitivity : 0.5 kgf/cm 2, Maximum Scale: 25 kgf/cm 2 Packer Hydraulic Packer Water Level Test Measuring accuracy: 1cm (b) Method Lugeon tests were carried out in every stage of the drill-hole after washing with clean water. The details of the test are as summarized Table Method Table Method of Lugeon Test Stage Method (single packer) Length of Test 5 meters (1 stage = 5m) Packer Hydraulic packer Pressure Steps 12 steps in total (0.5, 1, 2, 3, 4, 5, 7, 10, 7, 5, 3, 1 kgf/cm 2 ) Pressure Steps Measurement is more than 5 minutes. Injected flow measured and recorded every one minute after flow became stable. Measurement of Water Level Water level measured before and after the lugeon test. (c) Calculation of Lugeon Value Lugeon value is calculated by the following method: [Step1] Draw P-Q curve (P: actual pressure, Q: water discharge); [Step 2] Calculate water discharge when actual pressure is 10kgf/cm 2 (1MPa) (Figure 4.4.3); [Step 3] When actual pressure cannot reach 10kgf/cm 2 or critical pressure happens, calculate converted Lugeon value to extend the lower pressure region (Figure 4.4.4). P (kgf/cm 2 or MPa) P (kgf/cm 2 or MPa) P (kgf/cm 2 or MPa) Figure Q (l/min/m) Lugeon Value (Lu) P=10kgf/cm 2 =1 MPa Calculation of Lugeon Value P=10kgf/cm 2 =1 MPa Critical pressure Q (l/min/m) Converted Lugeon Value (Lu) Q (l/min/m) Converted Lugeon Value (Lu) Figure Calculation of Converted Lugeon Value 4-48 CTI Engineering International Co., Ltd. and

17 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (d) Calculation Method for Revision of Pressure Actual pressure is calculated by the following method for the revision of pressure (Figure 3.4.5). P = P 0 + W w x (h 1 - h 2 h 3 ) [kg/cm 2 ] 1) P : Actual pressure [kg/cm 2 ] P 0 : Gauge pressure [kg/cm 2 ] h 1 : Depth between pressure gauge and middle point of test section [m] h 2 : Depth between ground water level and middle point of test section [m] *) If there is pressured ground water in the test section, h 2 shall be depth between water head of pressured ground water and middle point of test section. h 3 : Head loss [m] W w : Unit weight of water per 1m [1.0tf/m 3 x 1m= kgf/cm 3 x 100cm =0.1kgf/cm 2 ] h 3 = a x Q 2 x L 2) Q : Water discharge [ltr/min] L : Length of the pipe [m] h 1 (value of L is nearly equal to the value of h 1 ) a : 7 x 10-5 [min 2 /ltr 2 ] Pressure gauge Return valve Flow meter Pump L Ground water level S h 1 h 2 S/2 Packer Middle point of test section S: Section length (3) Laboratory Tests Figure Schematic Model of Lugeon Test Samples were taken from drill hole cores and laboratory tests and analyses were performed in accordance with ASTM (Table ). Table Test Standards of Laboratory Tests and Quantities Item Test Standard Quantities Physical Property Test (including tests of specific gravity, absorption ratio and effective porosity) Unconfined Compression Test ASTM D Standard Test Method for Specific Gravity and Absorption of Rock for Erosion Control. ASTM D Standard Test Method for Unconfined Compressive Strength of Intact Rock Core Specimens. 25 samples 25 samples CTI Engineering International Co., Ltd. and 4-49

18 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Results of Geotechnical Survey (1) Drilling Results of drilling are as shown in the Annex _3 (Geologic Log and Drillhole Core Photo). Brief descriptions are given below. (a) BC-1 Site Schematic columnar section of BC-1 is as shown in Figure Geologic Conditions The BC-1 site mainly consists of granite (muscovite granite and biotite granite). Sometimes the site contains gneiss xenoliths and intercalated pegmatite vein. Sometimes pegmatite contains black columnar shaped crystals (determined tourmaline by X-ray powder method). Biotite granite and pegmatite contain garnet crystals of about 1mm in diameter. Small scaled faults (CF-1 and CF-2) were observed at the depth of 30.25m and 83.75m. Along CF-1, altered clay mineral was observed (determined feldspar origin kaolinite by X-ray powder method). Legend Geologic Division Rock Classifications Rock Mass Conditions At the depth of 1.8m, drill-hole encountered bedrock. The layer of 1.8m to 6.0m consists mainly of CL class rocks while 6.0m to 32.6m consists mainly of CM class rocks. Below 32.6m is mainly CH class rocks. Lugeon Value Permeability of Bedrock The layer of 5.0m to 15.0m shows high permeability (over 50Lu) while the layer of 15.0m to 45.0m shows a relatively low value (about 5Lu) except the 25m to 40m high permeability zone along CF-1. The layer of 45.0m to 100.0m shows low permeability values (below 2.0Lu). Figure Lugeon Value Rock Mass Classification Geologic Division Schematic Columnar Section of BC CTI Engineering International Co., Ltd. and

19 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (b) BD-1 Site Schematic columnar section of BD-1 is as shown in Figure Geologic Conditions This site mainly consists of granite (biotite granite and muscovite granite). Sometimes it contains intercalated pegmatite vein. Pegmatite contains black columnar-shaped crystals of tourmaline. Legend Geologic Divisions Small scaled faults (DF-1 and DF-2) were observed at the depth of about 87m and 57.20m. Rock Mass Conditions At the depth of 1.5m, drillhole encountered bedrock. The layer of 1.5m to 8.0m consists of mainly CL class rocks. The layer of 8.0m to 19.2m consists of mainly CM class rocks. Below 19.2m consists mainly of CH class rocks. Rock Classifications Permeability of Bedrock The layer of 5m to 15.0m shows relatively low value (about 5Lu) while 15.0m to 20.0m shows high permeability (27.8Lu). The layer of 20.0m to 100.0m shows low permeability values (below 2.0Lu). Lugeon Value Lugeon Value Rock Mass Classification Geologic Division Figure Schematic Columnar Section of BD-1 CTI Engineering International Co., Ltd. and 4-51

20 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (c) BE-1 Site Schematic columnar section of BD-1 is as shown in Figure Geologic Conditions The BE-1 Site mainly consists of psamitic schist. Sometimes the site contains intercalated pelitic schist, green rock, quartzite and siliceous schist. Psamitic schist is sandstone origin crystalline schist. Pelitic schist is pelitic rock (e.g., shale and mudstone) origin; crystalline schist relatively shows strong schistosity. Quartzite and siliceous schist are chert origin crystalline schist. Rock Mass Conditions At the depth of 0.25m, drillhole encountered bedrock. The layer of 0.25m to 3.4m consists mainly of CL class rocks. The layer of 3.4m to 16.0m consists mainly of CM-class rocks. Below 16.0m it consists mainly of CH class rocks. Permeability of Bedrock Legend Geologic Divisions Rock Classifications Lugeon Value The layer of 5.0m to 10.0m shows a relatively high value (11.3Lu). The layer of 10.0m to 30.0m shows intermediate permeability (5-10Lu) while the layer of 30.0m to 35.0m shows relatively low permeability values (2.2Lu). The layer of 35.0m to 100.0m shows low permeability values (below 2.0Lu). Lugeon Value Rock Mass Classification Geologic Division Figure Schematic Columnar Section of BE CTI Engineering International Co., Ltd. and

21 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (2) Lugeon Test Results of lugeon tests are as shown in Table At all sites, deep regions show low lugeon values. The BC-1 site shows a relatively high lugeon value. The occurrences of critical pressures are rare. Detailed results of lugeon test are as shown in Annex _5. Table List of Lugeon Test Results Drillhole No. BC-1 BD-1 BE-1 Stage Depth of Test(m) Lugeon Value ( ) Converted Lugeon value Critical Pressure kgf/cm² Maximum Pressure kgf/cm² (975.0) (651.6) (18.0) (62.0) (77.9) (2.3) (27.8) (11.3) CTI Engineering International Co., Ltd. and 4-53

22 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (3) Groundwater Level Relationships between drilling depth and groundwater level are shown in Annex _4. At every site, groundwater levels were stable. Water loss and spring was not observed. (4) Laboratory Test The list of laboratory test results is given in Table Detailed results of laboratory test are as shown in Annex _6. Five (5) samples were crashed along the latent crack to avoid the estimation of unconfined compression strength (σc). The relationship between rock species of drilling depth and σc is shown Figure There is no clear difference in granitic rocks. Granitic rocks have high σc (over 100MPa). Psamitic schist has relatively low σc (about 50MPa) but the strength is enough for dam foundation. With regard to rock hardness, the relationship between drilling depth and σc is shown in Figure Hardness rank A indicates over 100MPa σc while hardness rank B indicates MPa σc. Apparent specific gravity of all samples shows over 2.5g/cm 3 and absorption of all samples shows below 3%. These values are good for concrete aggregates. Table List of Laboratory Test Results Rock Species Pegmatite Muscovite Granite Garnet Bearing Biotite Granite Biotite Granite Green Rock Psamitic Schist Rank of Hardness Name of Drillhole Sample Depth (m) Center of Sample Depth (m) Apparent Specific Gravity (g/cm 3 ) Absorption (%) Unit Weight (g/cm 3 ) Unconfined Compression Strength (σc:mpa) Remarks B BC Weak Weathered B BC Rock A BC A BC A BC A BC A BC Garnet Poor A BC A BC A BC A BD A BD A BD A BD B BE B BE B BE B BE B BE B BE B BE B BE B BE B BE B BE Crashed along Latent Crack Crashed along Latent Crack Crashed along Latent Crack 4-54 CTI Engineering International Co., Ltd. and

23 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter Unconfined Compression Strength (σ c:mpa) Pegmatite Muscovite Granite Garnet Bearing Biotite Granite Biotite Granite Green Rock Psamitic Schist Centor of Sample Depth (m) Figure Relationship of Rock Species between Drilling Depth and σc 200 Unconfined Compression Strength (σ c:mpa) Rank of Hardness : A Rank of Hardness : B Centor of Sample Depth (m) Figure Relationship of Rock Hardness between Drilling Depth and σc CTI Engineering International Co., Ltd. and 4-55

24 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Comparison of Rock Mass Classifications in Dam Site (1) Dam Site C The characteristics of bedrock in Dam Site C are herein described based on the condition of Drillhole BC-1. Percentages of rock mass classification combination of subdivisions in BC-1 are as shown in Figure and the rock mass classification combination of subdivisions in BC-1 is as shown in Table % 50% 40% 30% 20% 10% 0% 50% 42% 4% CH class AⅡa AⅡb AⅢa BⅡa 4% 40% 35% 30% 25% 20% 15% 10% 5% 0% 37% 17% 10% 9% 6% 2% CM class 8% 8% 3% 1% AⅡc AⅢb AⅢc AⅣa BⅡc BⅢa BⅢb BⅣa CⅡa CⅡb 25% 20% 15% 15% 13% 24% CL class 16% 16% 10% 5% 6% 5% 6% 0% AⅤd BⅣb BⅣc BⅤd CⅣc DⅢa DⅢb DⅢc Dominant combination Figure Percentages of Rock Mass Classification Combination of Subdivisions in BC-1 Hardness A B C D E Table Rock Mass Classification Combination of Subdivisions in BC-1 Drillhole Core Condition of Crack Shape a b c d Ⅰ B Ⅱ CH CH CM - Ⅲ CH CM CM - Ⅳ CM Ⅴ CL Ⅰ Ⅱ CH - CM - Ⅲ CM CM - - Ⅳ CM CL CL - Ⅴ CL Ⅱ CM CM - - Ⅲ Ⅳ - - CL - Ⅴ Ⅲ CL CL CL - Ⅳ Ⅴ Ⅵ Ⅶ D Dominant Combination 4-56 CTI Engineering International Co., Ltd. and

25 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (2) Dam Site D The characteristics of bedrock in Dam Site D are herein described based on the condition of Drillhole BD-1. Percentages of rock classification combinations of subdivisions in BD-1 are as shown in Figure and rock mass classification combination of subdivisions in BD-1 is as shown in Table % 60% 50% 40% 30% 20% 10% 0% 61% 17% 10% CH class 7% 6% AⅠb AⅡa AⅡb AⅢa BⅡa 50% 40% 30% 20% 10% 0% 42% 20% 12% 8% CM class 13% 5% AⅢb AⅣa BⅡb BⅡc BⅢb CⅡa 70% 60% 50% 40% 30% 20% 10% 0% 65% 60% CL class 49% 50% 40% D class 26% 30% 29% 23% 20% 8% 1% 10% 0% BⅢc BⅣc CⅢc CⅣc DⅤd DⅥd EⅦd Dominant combination Figure Percentages of Rock Mass Classification Combination of Subdivisions in BD-1 Hardness A B C D E Table Rock Mass Classification Combination of Subdivisions in BD-1 Drillhole Condition of Crack Core Shape a b c d Ⅰ B CH - - Ⅱ CH CH - - Ⅲ CH CM - - Ⅰ Ⅱ CH CM CM - Ⅲ - CM CL - Ⅳ - - CL - Ⅱ CM Ⅲ - - CL - Ⅳ - - CL - Ⅴ Ⅲ Ⅳ Ⅴ D Ⅵ D Ⅵ Ⅶ D Dominant Combination CTI Engineering International Co., Ltd. and 4-57

26 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (3) Dam Site E The characteristics of bedrock in Dam Site E are herein described based on the condition of Drill-hole BE-1. Percentages of rock mass classification combinations of subdivisions in BE-1 are as shown in Figure and rock mass classification combination of subdivisions in BE-1 is as shown in Table % 80% 70% 60% 50% 40% 30% 20% 10% 0% CH class 80% 12% 4% 4% AⅡa AⅢa BⅠa BⅡa 80% 70% 60% 50% 40% 30% 20% 10% 0% 73% 6% CM class 20% BⅢa BⅢb BⅣa 30% 25% 28% CL class 23% 20% 15% 10% 5% 8% 15% 15% 11% Dominant combination 0% BⅣc BⅣd CⅣb CⅣc CⅣd CⅤd Figure Percentages of Rock Mass Classification Combination of Subdivisions in BE-1 Table Hardness A B C D E Rock Mass Classification Combination of Subdivisions in BE-1 Drillhole Condition of Crack Core Shape a b c d Ⅰ Ⅱ CH Ⅲ CH Ⅳ Ⅰ CH Ⅱ CH Ⅲ CM CM - - Ⅳ CM - CL CL Ⅱ Ⅲ Ⅳ - CL CL CL Ⅴ CL Ⅲ Ⅳ Ⅴ D Ⅵ Ⅶ Dominant Combination 4-58 CTI Engineering International Co., Ltd. and

27 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (4) Comparison of Rock Mass Classifications in Dam Site Rock mass classification combinations of subdivisions in BC-1 and BD-1 tend to be the same. On the other hand, the combination in BE-1 is different (Table ). BC-1 and BD-1 take relatively excellent regions and BE-1 takes a relatively inferior region. Therefore, the shear strength of bedrock in Dam Site E is supposed to be weaker than those of Dam Site C and Dam Site D. This difference is due to the difference in rock species. Table Difference of Rock Mass Classification Combination of Subdivisions in BC-1, BD-1 and BE-1 Drillhole Core Condition of Crack Hardness Shape a b c d Ⅰ B CH - - Ⅱ CH CH CM - A Ⅲ CH CM CM - Ⅳ CM Ⅴ CL Ⅰ CH Ⅱ CH CM CM - B Ⅲ CM CM CL - Ⅳ CM CL CL CL Ⅴ CL Ⅱ CM CM - - C Ⅲ - - CL - Ⅳ - CL CL CL Ⅴ CL Ⅲ CL CL CL - D Ⅳ Ⅴ D Ⅵ D E Ⅶ D Dominant Combination in Dam Site C and D (BC-1 and BD-1) Dominant Combination in Dam Site E (BE-1) CTI Engineering International Co., Ltd. and 4-59

28 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Comparison of Dam Sites (1) Geologic Condition Geologic profiles along and across the dam axis are shown Figure Dam Site C and Dam Site D mainly consist of granite. Low angle thin pegmatite veins are intercalated in granite. Their boundaries are closed and there is no weak layer at boundaries. Dam Site E mainly consists of psamitic schist. Thin bedded green rock and quartzite are intercalated in psamitic schist. Their schistosity is parallel to the bedding plane. Minor scale faults were observed in every dam site. Their directions are almost parallel to the dam axis. Figure Geologic Profile along and across Dam Axis 4-60 CTI Engineering International Co., Ltd. and

29 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (2) Condition of Bedrock Rock mass classification profiles along and across the dam axis are as shown in the following figures. Figure Rock Mass Classification Profiles Along and Across Dam Axis Hard rock masses, which are classified in CH and CM classes, are distributed relatively at shallow depths from the ground surface in every dam site. CTI Engineering International Co., Ltd. and 4-61

30 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (1) Condition of Basement Permeability Distribution profiles of Lugeon value along and across the dam axis are shown in the following figures. Figure Lugeon Value Distribution Profiles Along and Across Dam Axis Low Lugeon value rock mass are distributed relatively at shallow depths from the ground surface in every dam site CTI Engineering International Co., Ltd. and

31 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter Construction Material of Dam Dominant dam types for Salang Dam are concrete gravity dam and center core rock-fill dam. For concrete gravity dam, it is necessary to obtain the large amount of concrete aggregate. For rockfill dam, it is necessary to obtain larger amount of course materials for rock material and fine materials for core (impervious) material. We describe below about the distribution of these materials around the project area Concrete Aggregate In a process of consolidation of concrete, cement water reaction produce an increase in temperature. Temperature rise of concrete may cause crack by expansion and contraction lead by heating. For construction of concrete dam, it is necessary to keep the amount of cement to low to suppress the occurrence of crack. Therefore, larger sized aggregate (generally maximum grain size is 150mm) is necessary to reduce cement amount in the dam concrete. Large amount of hard and massive rock masses such as granite, gneiss, gabbro, psamitic schist and crystalline limestone distribute around the dam site. River bed deposit and terrace deposit containing cobble and boulder derived from these massive rocks distribute along the Salang River. River bed deposit and terrace deposit have relatively large area. Concrete aggregate can be obtained from river bed deposit and terrace deposit, basically. If the amount is not enough or if they will not be used, the aggregate can be adjusted by exploitation of the quarry to the massive rock distribution area; for example, the alternative dam site which is good for quarry. The result of laboratory test of the sample collected from the alternative dam site show good quality for concrete aggregate as mentioned at 4.4.7(4). Serpentinizated ultramafic rock which distribute at the northern project area is not suitable for concrete aggregate because it is soft, weak to weathering and due to the occurrence of pop-out in concrete. Pelitic schist which distribute at the northern project area is not also good for quarry, because it has many cracks along the schistosity, it is difficult to obtain large aggregate, and the shape is plane - low yield is predicted by the deep weathering. Lithologic description of project area is as shown in Annex _1. From the microscopic observation for main rocks around the project area, harmful minerals for concrete aggregate such as alkali aggregate reaction mineral (e.g., tridymite, cristobalite, etc.) and swelling minerals (e.g., smectite, laumontite, etc.) is not observed Course Material for Rockfill Dam Rock material can be obtained by exploitation of the quarry in the massive rock distribution area in the reservoir area. River bed deposit and terrace deposit are also suitable for rock material. Filter material will be obtained from river bed deposit and terrace deposit. Riprap material will be obtained from the quarry in the massive rock such as granite and gneiss distribution area. Boulder of river bed deposit and terrace deposit can be also used for riprap material Core Material for Rockfill Dam (1) Selection of Survey Area The availability of soil material to be utilized as core material in the impervious zone of rockfill dam was studied. Necessary characteristics for core material are low permeability and strength which shall CTI Engineering International Co., Ltd. and 4-63

32 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for be enough to construct the embankment and shall not contain harmful materials such as organic matter. Core material is not available around the dam site and reservoir area. The five (5) sites for site survey, namely; BA-A, BA-B, BA-C, BA-D and BA-E, were selected from the areas where soft sediment is distributed. The following conditions shall be considered to select candidate borrow areas. (See Figure and Figure 4.5.2): Borrow areas shall be located within the radius of about 10km from Dam Site A. Generally, old soft sediment contains large quantities of fine material because of weathering. The area of Q 34 ac (fan alluvium and colluviums) and Q 3 loe (loess) (Figure 4.5.2) are to be selected for the object strata to be surveyed. Survey areas shall be located along the principal road, considering material transportation. Residential area and farmland are excluded as survey area. N BA-D BA-B BA-C BA-A BA-E 0 1km Figure Survey Areas for Borrow Area of Fine Material 4-64 CTI Engineering International Co., Ltd. and

33 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 N BA-B BA-C BA-D BA-A R=10km BA-E R=20km Observed Strata After Lindsay et al. 2005:USGS Geologic map Figure Distributions of Soft Sediment and Locations of Survey Area for Borrow Area CTI Engineering International Co., Ltd. and 4-65

34 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for (2) Results of Field Survey (a) BA-A Site (appropriate) There is no house around the BA-A Site. A part of this area is used as graveyard. The soft sediment around the BA-A Site seems to be the weathered alluvial fan deposit. Sediment contains a large amount of fine materials (Figure 4.5.3). This site is suitable as a borrow area for the core material. BA-A Figure Soft Sediment around the BA-A Site (b) BA-B Site (appropriate) The BA-B Site is a vacant lot located behind the orchard along the road. Soft sediment around the BA-B Site contains fine material and small pebbles (Figure 4.5.4). This site is suitable as a borrow area for the core material. BA-B Figure Soft Sediment around the BA-B Site (c) BA-C Site (inappropriate) There are some existing borrow pits in the BA-C Site. The soft sediment around the BA-C Site seems to be alluvial fan deposit based on the observation of excavated slope in the existing pit. It contains a large amount of coarse material and minimal amount of fine material (Figure 4.5.5). This site is not suitable as a borrow area for the core material CTI Engineering International Co., Ltd. and

35 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 BA-C Figure Soft Sediment around the BA-C Site (d) BA-D Site (appropriate) There are some existing borrow pits in the BA-D Site. The soft sediment around the BA-D Site seems to be loose and contains a large amount of fine materials based on the observation of the excavate slope in the existing pit (Figure 4.5.6). This site is suitabe as a borrow area for the core material. BA-D Figure Soft Sediment around the BA-D Site (e) BA-E Site (inappropriate) There are some houses and an irrigation canal in the BA-E Site. Its condition is not good for as a borrow area. From the observation result of cut-off in the slope, the soft sediment around the BA-E Site is terrace deposit containing large amounts of sand, gravel and minimal amount of fine material (Figure 4.5.7). This site is not suitable as a borrow area for the core material. BA-E Figure Soft Sediment around the BA-E Site CTI Engineering International Co., Ltd. and 4-67

36 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for Summary of Construction Materials Survey The construction materials survey is as summarized below. Concrete aggregates and coarse materials are available in/around the dam site and reservoir area. Core materials are available at sites BA-A, BA-B and BA-D. Further geologic survey is necessary to identify the potential of borrow areas for core material. Besides the borrow areas listed above, the weathered zone of the pelitic schist and/or green rock can be a borrow area for the core material. The pelitic schist and/or green rock are weak against weathering. Further geologic survey is necessary. 4.6 Concluding Remarks and Future Investigations Concluding Remarks Geologic conditions around the alternative Salang dam sites were investigated based on aerial photo interpretation and field survey. Five (5) alternative dam sites were selected based on geomorphic characteristics. One (1) drilling was done on each axis of three (3) relatively good dam sites. The summary of results is as shown below. Detail geologic maps and profiles are as shown in Annex _8 and Annex _9. (1) Quaternary Fault Eight (8) Quaternary faults named in literatures as F-1 to F-8 exist in the radius of 10km from Alternative Dam Site A. They are over 5km from the alternative dam site and their directions do not tend to reach the site except the F-1 fault which is classified as Category C (Figure 4.1.6). Thirty-nine (39) Lineaments were detected in the radius of 10km from Alternative Dam Site A by preliminary areal photointerpretation. Except Lineament (1), they are far enough from the alternative dam site and their directions do not tend to reach the site. Lineament (1) is classified as L3 which is the most indistinct Lineament (Table 4.1.3), and locates in the extended area of F-1 fault. The relatively large F-A fault was observed at the agree point of Lineament (1) in the project area. There is low probability that the F-A fault is a Quaternary fault because displacement caused by fault movement on the Quaternary strata could not be observed. Under present condition, there is no decisive evidence that F-A fault is not Quaternary fault. However, the F-A fault will not cause a serious problem because it is about 500m away from the alternative dam site. (2) Landslide around the Project Area Small scale landslides could be observed at the eight sites. The largest landslide among them is LS-R2. Further detailed investigation would be necessary in case Dam Site D is selected as the optimum dam site because LS-R2 is affected by the water action of reservoir. Landslides at the other seven sites are relatively small; they will not cause serious problems CTI Engineering International Co., Ltd. and

37 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 (3) Geologic Problem on the Reservoir Relatively thick bedded crystalline limestone is distributed in the northern project area. In case Dam Site E is selected as the optimum dam site, the crystalline limestone distributed in the reservoir should be taken into account. Since the rock body of crystalline limestone trending west to east and its succession is not large in the USGS geologic map, there is low possibility of leakage from the reservoir to another river. (4) Conditions of Geology, Rock Mass and Permeability in the Alternative Dam Sites Conditions of geology, rock mass and permeability in Dam Site C, D and E are as shown in Table based on the drilling data. They seem to show a good condition for the foundation of a concrete gravity dam and a rockfill dam. On the other hand, bedrock of Dam Site A consists mainly of granite similar to that of Dam Site C and Dam Site D. Bedrock of Dam Site B consists mainly of gabbro similar to granite. There is no large difference of geomorphic and rock mass condition in alternative dam sites based on the field survey. Therefore, it is expected that the conditions of rock mass and permeability of Dam Site A and Dam Site B are as good as Dam Site C and Dam Site D. Table Conditions of Geology, Rock Mass and Permeability Dam Site C D E Geomorphology Geology Condition of Rock Mass in Drillhole Permeability in Drillhole Main Rock Species and Its Compressive Strength Remarks Applicability as Dam Foundation Below EL. 1,950m (dam height about 170m) is placed in the stricture. Bedrock consists of mainly granite which contain gneiss xenolith and pegmatite vein. Boundaries of xenolith and vein are closed. Small scaled faults (CF-1 and CF-2) were observed. Rock mass classification in BC-1: Depth 6-33m: mainly CM class Depth m: mainly CH class Permeability in BC-1: Depth 5-15m: over 50Lu. Depth 15-45m: almost 5Lu. Depth m: below 2Lu Main rock species: granite Unconfined compressive strength: over 100MPa Outcrop is rare in the upper part of left bank. Applicable as dam foundation of Concrete Gravity Dam and Rockfill Dam. Below EL. 2,020m (dam height about 120m) is placed in the stricture. Bedrock consists of mainly granite which contains pegmatite vein. Boundaries of vein are closed. Small scaled faults (DF-1 and DF-2) were observed. Rock mass classification in BD-1: Depth 8-19m: mainly CM class Depth m: mainly CH class Permeability in BD-1: Depth 5-15m: almost 5Lu. Depth 15-20m: 27.8Lu. Depth m: below 2Lu Main rock species: granite Unconfined compressive strength: over 100MPa There is relatively large landslide (LS-R2) in the reservoir. Applicable as dam foundation of Concrete Gravity Dam and Rockfill Dam. Below EL. 2,100m (dam height about 150m) is placed in the stricture. Bedrock consists of mainly psamitic schist which contain intercalated pelitic schist, green rock, quartzite and gabbro. Bedding plane and schistosity dip to the upstream by middle angle. Small scaled fault (EF-1) was observed. Rock mass classification in BD-1: Depth 4-16m: mainly CM class Depth m: mainly CH class Permeability in BE-1: Depth 5-10m: 11.3Lu. Depth 10-35m: almost 5Lu. Depth m: below 2Lu Main rock species: psamitic schist Unconfined compressive strength: over 50MPa Crystalline limestone distribute in the reservoir. Applicable as dam foundation of Concrete Gravity Dam and Rockfill Dam. (5) Construction Material of Dam It is assumed that concrete aggregate for concrete gravity dam and coarse materials for rockfill dam will be taken from the neighborhood of dam site and reservoir. CTI Engineering International Co., Ltd. and 4-69

38 Chapter 4 The Feasibility Study on Urgent Water Resources Development and Supply for It seems that there is no site which has the potential to be a borrow area for the core material of rock-fill dam in the area of about 10km away from Dam Site A Future Investigations This survey is a preliminary feasibility study executed to grasp the outline of geological conditions. It is necessary to conduct a more detailed survey for the purpose of constructing the Salang Dam. With regard to Dam Site E which has a relatively good geologic and geomorphologic condition, it is proposed that the plan be surveyed for Salang Dam. The items of survey are as shown in Table List of geophysical prospecting survey and drilling survey is as shown in Table and Table Location of geophysical prospecting survey and drilling survey is as shown in Figure and Figure Table Items of Survey for Salang Dam Items Planimetry (Scale: 1/500) Cross Sectional Survey Geologic Survey Geophysical Prospecting Survey Drilling Survey Lugeon Test Quantities Complete Set 7 Line, 5,850m in total Complete Set 7 Line, 5,850m in total 9 Drillhole, 1,270m in total 245 Times Table List of Geophysical Prospecting Survey for Salang Dam Name of Line Length (m) Remarks UD0 950 Along Axis of Dam D U L Along Riverbed R R L Total 5,850 Table List of Planned Drilling Survey for Salang Dam Drillhole No. Drill Length (m) Lugeon Test (Times) Purpose of Survey BE Comprehend geologic condition of river bed. BE Comprehend geologic condition of river bed. BE Comprehend geologic condition of right bank. BE Comprehend geologic condition of left bank. BE Comprehend groundwater level of right bank. BE Comprehend groundwater level of left bank. BE Comprehend geologic condition of river bed. BE Comprehend geologic condition of right bank. BE Comprehend geologic condition of left bank. Total 1, CTI Engineering International Co., Ltd. and

39 The Feasibility Study on Urgent Water Resources Development and Supply for Chapter 4 Figure Location Map of Planned Geophysical Prospecting Survey and Drilling survey Figure Profile of Planned Drilling Survey CTI Engineering International Co., Ltd. and 4-71