Geotechnical Investigation of 32 Chapter Street, Saint Albans, Christchurch

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1 IAG (NZ) Ltd C/- Harker Underground Construction Ltd 28 February 2013 RE: Geotechnical Investigation of 32 Chapter Street, Saint Albans, Christchurch Introduction and Background Geoscience Consulting (NZ) Ltd (Geoscience) was requested by Harker Underground Construction Ltd (on behalf of IAG (NZ) Ltd) to undertake a geotechnical investigation of the subject property (herein referred to as the site ). We have not been provided with a floor level survey and are unable to provide final foundation recommendations until we have that information given the nature of the site as discussed below. We understand the dwelling at the site sustained damage as a result of the recent earthquakes and that you require a detailed geotechnical assessment of the ground conditions in order to determine a suitable foundation option for the proposed repair. Our scope of works specifically excluded assessment of the structural integrity of the dwelling. The scope of this study consists of: Desktop study of relevant publically available geotechnical and geological publications; Undertake a visual inspection of the site to identify land damage following the recent earthquakes; Review of publically available Earthquake Commission (EQC) and Environment Canterbury (ECan) borehole data to comment and summarise the subsurface materials; Perform two hand auger borehole and Scala Penetrometer (Scala) tests to a target depth of 2.9 m; Organisation, technical supervision and logging of one Machine Borehole to approximately 15 m depth; An assessment of liquefaction potential for the site; and Presentation of a report outlining our findings on the ground conditions and including geotechnical advice on foundation conditions. Site Description The site is located in the Saint Albans suburb of Christchurch on a relatively flat section of approximately 1,100 m 2. It is bound to the north, east, south and west by residential properties. Saint Albans creek crosses the southern corner of the site approximately 15 m from the dwelling. The Canterbury Earthquake Recovery Authority (CERA) has mapped the site within the Green Zone where buildings are typically considered suitable for repair or rebuilding. The Ministry (formally the Department of Building and Housing) has divided the CERA Green Zone into Technical Categories. This site is currently classified as TC3, where moderate to significant land damage from liquefaction is possible in future large earthquakes and specific geotechnical investigation and engineering design is required. Geoscience Consulting (NZ) Limited PO Box 110, Lyttelton 8841, New Zealand T (+64) (3) F (+64) (3) Geoscience ref.:

2 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch Publically Available Information CERA has established an online Canterbury geotechnical database which provides access to geotechnical investigations, aerial photography, groundwater level data, field observations and mapping provided by EQC commissioned engineers, and LiDAR surveys. Subsurface Data GNS (Brown, 1992) maps the site as being underlain by dominantly alluvial sand and silt overbank deposits of the Springston Formation. Groundwater is regionally mapped between 1 m and 2 m below the ground surface at the time of the Canterbury Earthquake Sequence. The closest piezometer measurement is approximately 80 m south of the site. We have reviewed publically available subsurface data, consisting of a nearby Cone Penetration Test (CPT 734) sounding performed by Tonkin and Taylor (T&T) located at the neighbouring property to the southwest. The soil behaviour types as interpreted by the CPT indicate that soil materials consisting of interbeds of clays and silty clay and sand and silty sand are encountered from ground surface extending to a depth of 11 m. Underneath the upper layer is a layer of sand and silty sand to a depth of 16.5 m. From approximately 16.5 m extending to the bottom of the CPT at 22 m depth the sand is underlain by silty sand and sandy silt. Groundwater condition was not reported in the T&T data. Aerial Photography Aerial photographs were taken in the days following each of the major earthquakes in Canterbury. A review of the photographs indicates moderate to significant volumes of ejected sand and silt at the site and surrounding areas occurred during the Canterbury Earthquake Events. Ground Cracking Ground crack locations were mapped by the EQC following the September 2010 and February 2011 events. The following is noted by the EQC: the crack mapping is incomplete and only observations made by the mapping teams are presented. In particular, the mapping following the 4 Sept 2010 Earthquake was incomplete before the 22 Feb 2011 Earthquake occurred. The mapping shows a series of ground cracks of up to 200 mm wide were located along the alignment of Saint Albans creek in the vicinity of the site, but none of these wide ground cracks were mapped closer than approximately 25 m from the site. A ground crack of up to 5 m length and less than 10 mm wide was mapped along the northern perimeter of the site on Chapter Street. LiDAR and Ground Movement LiDAR surveys prepared on behalf of the EQC indicate on the order of approximately 0.5 m to 1.0 m of total vertical movement (subsidence) and an event specific settlement of between 100 mm to 300 mm during each of the Canterbury Earthquake Events. In general, approximately 360 mm of local horizontal deformation towards the northwest has cumulatively occurred between the September 2010 and December The LiDAR surveys cannot differentiate between localized liquefaction induced settlement/lateral stretch and regional local displacements. It should be noted that these values are for approximation only. Geoscience ref.: February 2013

3 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch Floor Levels The Christchurch City Council (CCC) and CERA have released updated floor levels for properties in the Avon, Heathcote and Styx river catchments, as well as Sumner. The following data is reported for this site: Interim Floor Level: m above the Christchurch City Datum Average Ground Level: m above the Christchurch City Datum Modelled 50 Year Flood Level: 0 m above the Christchurch City Datum Modelled 200 Year Flood level: 0 m above the Christchurch City Datum We note that the site is located outside of the CCC City Plan Flood Management Area. Site Investigation Geoscience visited the site on the 18 th of January 2013 and made the following observations: The site is relatively flat and the Saint Albans creek is located at the southern corner of the site approximately 15 m from the dwelling. The bottom of the creek is approximately 0.5 m below adjacent site grade and the creek is measured 1 m wide from top of banks. The dwelling is a timber framed structure with light/medium weight cladding on a perimeter concrete foundation with internal piles (Type B1 as defined by the DBH). A detached single garage with light/medium weight cladding on a concrete slab on grade foundation is located to the southwest of the dwelling. We observed cracking (<5 mm wide) in the foundation and separation in the cladding (<5 mm wide). Observed movement of up to 50 mm at the southwest side of the dwelling. Settlement was also observed at the northeast side of the dwelling. Damaged to the chimney was observed. We observed cracking (up to 50 mm wide) in the paved driveway. We observed undulation in the pavement of up to 100 mm and oscillation cracking of up to 20 mm across the site. Remnant of ejected sand/silt was observed at the southeast corner of the dwelling. The site location plan and photographs are presented as attachments to this letter report. Machine Borehole Pro-Drill Ltd drilled one machine borehole to a target depth of m. The boring was performed using a track mounted drill rig with 63-mm diameter rotary core. The penetration of the sampler in the native materials was recorded as the number of blows needed to drive the sampler 450 mm in 75-mm increments. The logs record blow count results as the actual number of blows required for the last 300 mm of penetration; no conversion factors have been applied. Standard Penetration Tests (SPTs) were performed at 1.5 m intervals using standard penetration test methods. The machine borehole log is presented as an attachment to this letter report and is written in accordance with the New Zealand Geotechnical Society field classification guidelines (NZGS, 2005). Geoscience ref.: February 2013

4 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch Hand Auger Borehole and Scala Penetrometer Testing In addition to the Cone Penetrometer Testing, Geoscience completed two hand auger boreholes and associated Scala Penetrometer (Scala) tests to a maximum depth of 3 m before reaching target depth. Groundwater was encountered at 2.9 m depth in hand auger borehole HA01. Groundwater was not encountered in the hand auger borehole HA02. Full logs are presented as attachments to this letter report and are written in accordance with the New Zealand Geotechnical Society field classification guidelines (NZGS, 2005). Summary of Subsurface Conditions The material encountered in our subsurface investigations is broadly consistent with published mapping, as summarised in Table 1 below: Table 1: Summary of Subsurface Conditions Encountered in Ground Investigations Depth (m) Soil/Behaviour Type Density/Consistency 0.0 up to 0.6 FILL/TOPSOIL 0.6 to 3.0 Interlayering of SILT and sandy SILT Soft to Very Stiff 3.0 to 5.0 SILT and sandy SILT Firm 5.0 to SAND and silty SAND Loose to Medium Dense Organic material and wood pieces were encountered in our machine borehole extending from the ground surface to approximately 13 m depth. Soil Classification For the purpose of seismic design, we consider the soil classification in line with NZS :2004 to be Class D Deep or Soft Soil. Seismicity The Ministry has issued guidance for ground accelerations that should be used for assessment of liquefaction triggering in Canterbury. For Category D and Importance Level 2 sites, these are 0.13 g for the Serviceability Limit State (SLS) case (25 year return period) and 0.35 g for the Ultimate Limit State (ULS) case (500 year return period), both for magnitude 7.5 events. Bradley and Hughes (on behalf of EQC) have developed a contour map of the conditional median peak ground accelerations (PGA) interpolated from data measured at various recording stations during the recent Canterbury earthquake events. The PGA contour maps were created by combining the predication from an empirical ground motion model of the fault rupture with the PGA recorded at any adjacent strong motion states. According to the published contour maps, the site has experienced the following event specific conditional median PGAs (Table 2). Geoscience ref.: February 2013

5 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch Table 2: Summary of Conditional Median PGA Events 4 Sept Feb Jun Dec 2011 (M w 7.1) (M w 6.2) (M w 5.6) (M w 5.9) PGA (g) PGA 7.5 (g)* *Using Idriss and Boulanger (2008) magnitude scaling factor Liquefaction Analyses We have assessed the likelihood of liquefaction triggering and post-liquefaction induced vertical settlement occurring at the site using the SPT data following the methodology outlined by Youd et al. (2001); and using the CPT data from the neighbouring property following the methodology outlined by Idriss and Boulanger (2008) and Zhang et al. (2002). We have assumed a minimum groundwater depth of 1 m in the analysis based on shallowest depth to groundwater recorded during the 2010 and 2011 Canterbury Earthquake Events as provided by EQC. Table 3 presents the results of our liquefaction analyses under ULS and SLS loading. Table 3: Summary of Liquefaction Analyses Calculated Vertical Settlement* Design Case MB01 T&T CPT Total Upper 10 m Total Upper 10 m ULS 470 mm 400 mm 360 mm 220 mm SLS 310 mm 300 mm 270 mm 200 mm *For an undeveloped site. Settlements beneath buildings are likely to be greater. According to the results of our SPT based liquefaction analysis, the material underlying the site is potentially liquefiable and the associated seismic settlement is mainly contributed by the upper 14 m of subsurface material. Our analysis is solely based on SPT blow counts recorded during machine boring. Based on guidelines developed by Bray and Sancio (2006), the Plasticity Index and moisture content of fine grained material are used in evaluating susceptibility to liquefaction. Owing to the lack of laboratory testing on the silt and silty sand materials encountered within the upper 10 m below ground surface, we have conservatively assumed the material has low plasticity and are susceptible to liquefaction in our analysis. Our analysis concludes that 400 mm of liquefaction-induced vertical settlement is estimated in the upper 10 m under ULS loading and up to 300 mm under SLS loading. Additionally, we have assessed the likelihood of liquefaction triggering and post-liquefaction induced vertical settlement occurring at the site using the CPT 734 data obtained from the neighbouring site following the methodology outlined by Idriss and Boulanger (2008) and Zhang et al. (2002), respectively. Based on our liquefaction analysis, potentially liquefiable material under ULS design Geoscience ref.: February 2013

6 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch shaking is located between 1.5 m to 19.5 m depths. Total settlement contributed by the upper 10 m of site material is approximately 220 mm and 200 mm under ULS and SLS loading, respectively. We have also utilised our liquefaction model to estimate settlements at the site considering recorded conditional median ground motions provided by published contour maps for events during September 2010, February 2011, June 2011, and December Our analysis provided estimated settlements in the range of 140 mm to 220 mm. In general, the vertical deformation reported in the LiDAR mapping prepared by the EQC reported vertical deformations ranging from 100 mm to 300 mm of subsidence during each of the 2010 and 2011 earthquake events. Based on the result of our analysis, the model using CPT provided results that are generally consistent with those presented in vertical deformation reported in the LiDAR mapping prepared by the EQC. It is our opinion that the CPT model is a better representation of the site condition because a continuous soil profile is used to evaluate the settlement. We believe liquefaction related settlement of up to 250 mm can be expected at the site as a result of a seismic event. It is our opinion that the site has likely experienced shaking similar to SLS design conditions, but has not experienced shaking near the ULS design requirements (the conditional median PGA of the February event is equivalent to 0.23g when applying a magnitude scaling factor to M7.5 as recommended by Idriss and Boulanger, 2008). By following the procedure proposed by Ishihara (1985), significant surface manifestation of liquefaction at this site is expected. Owing to the thickness of the potentially liquefiable layer and relatively thin non-liquefiable surface layer, sand boil resulting in ejection of sand/silt at the surface is likely to occur at the site under ULS shaking. This is evidenced by the significant sand/silt ejecta observed at the site during the Canterbury Earthquake Events. Given these conditions, the total building settlement attributing from a combination of volumetric strain of the liquefiable layer and loss of bearing support related to sand boils are likely to exceed those calculated in the above analysis. The groundwater depth recorded at the site is between 1.0 m to 2.0 m and the depth of the creek is approximately 0.5 m below site grade, these conditions do not give rise to lateral spreading at the site. However, considering the observed separation in the paved driveway and the mapped ground cracking, we modelled lateral spreading using the CPT data under ULS and SLS design earthquakes. We calculated the liquefaction-induced lateral displacement by utilising methodology described by Zhang, Robertson and Brachman. For the purposes of analysis, we used a groundwater level of 0.5 m depth and the site was considered Level Ground with a Free Face. Based on our analysis, we estimate maximum liquefaction-induced lateral displacement of up to 30 mm under ULS and SLS design earthquake shaking. This estimate of lateral displacement is generally within the range of observed separation of less than 50 mm wide cracks at the paved driveway and the LiDAR measurements of less than 10 mm. However, the estimated lateral displacement only occurs when groundwater is at a depth of 0.5 m. This shallow groundwater level was neither observed nor recorded at our site and as such the potential for lateral spreading and associated displacement at the site is considered low. The machine borehole and CPT data (including liquefaction analyses) is presented as an attachment to this letter report. Liquefaction Hazard Summary A summary of the ground performance expectations for the site is presented in Table 4 below, in accordance with the MBIE guidelines. Geoscience ref.: February 2013

7 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch Table 4: Summary of Ground Performance Expectations* Performance Category Land Damage Type Land Damage Category SLS ULS Vertical Settlement (in the upper 10 m) Lateral Stretch Global Lateral Movement TC3 Potentially Significant TC3 Minor to Moderate TC3 Minor to Moderate *As per Tables 12.1, 12.4 and 12.5 of the MBIE guidelines. Geotechnical Recommendations Based on our site investigation and observations we consider the TC3 classification to be appropriate. As outlined in the MBIE guidelines, expected settlements for TC3 sites under ULS and SLS design loads are greater than 100 mm and greater than 50 mm, respectively. We recommend designing foundations to handle the settlements provided in Table 3. We consider the site suitable for repair subject to the following recommendations. We recommend a structural assessment to evaluate the foundation distress and practicality of relevelling and repair. Considering the volumes of ejecta observed in aerial photography during the Canterbury Earthquake Events and the SLS settlement is anticipated to be more than 200 mm within the upper 10 m of subsurface material, a floor level survey is recommended to be performed to evaluate if a repair is appropriate for the dwelling. Based on our field observations, the site appears to have performed well despite significant vertical settlement and depending on the magnitude of differential settlement that the dwelling has experienced to date, the MBIE guidelines will allow either a foundation repair (if the differential settlement is less than 100 mm) or may require a full foundation replacement (if the differential settlement is greater than 100 mm or there are significant cracks in the perimeter foundation, or if the majority of the floor piles need replacing). If the differential settlement does not exceed those allowed for a foundation repair we recommend repairing the foundation in line with Section 14 and particularly Figure 14.1 of the MBIE guidelines. Based on our Scala test results, it is our opinion that a static geotechnical Ultimate Bearing Capacity of 150 kpa can be assumed for material below the topsoil/fill at 0.6 m depth. Re-levelling options may include underpinning the perimeter foundations with injected resin or grout or hydraulic jacking or other alternatives. If replacing portions of the perimeter foundation or replacing piles, we recommend these foundation elements bear on the native sand immediately below the 0.6 m depth to maximise the distance between the base of the foundation and the shallow potentially liquefiable soil and therefore minimise the risk of the foundations punching into this layer during future liquefaction events. Additional Considerations New foundation elements should be designed by a Chartered Professional Engineer practising in foundation design. We advise that future building work takes into consideration the recommendations of the MBIE guidelines. Geoscience ref.: February 2013

8 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch References If structures on the site are to be rebuilt instead of repaired we recommend you contact Geoscience for guidance. Brown, L.J., Weeber, J.H., 1992: Sheet 1 - Geology of the Christchurch Urban Area 1:25,000. Institute of Geological and Nuclear Sciences, Lower Hutt. Canterbury Regional Council, 2007: Christchurch City Waterways Survey Maps. Forsyth, P.J.; Barrell, D.J.A; Jongens, R. 2008: Sheet 16 - Geology of the Christchurch Area 1:250,000. Institute of Geological and Nuclear Sciences, Lower Hutt Idriss, I.M. and Boulanger, R.W. 2008: Soil Liquefaction during Earthquakes Earthquake Engineering Research Institute Monograph MNO12, pp New Zealand Geotechnical Society, 2005: Guideline for the Field Classification and Description of Soil and Rock for Engineering Purposes. Standards Association of New Zealand, 2004: Structural Design Actions, Part 5: Earthquake Actions New Zealand, NZS :2004. Standards New Zealand, Wellington. Ministry of Business, Innovation and Employment (MBIE), December 2012: Repairing and Rebuilding Houses affected by the Canterbury Earthquakes ( Zhang, G.; Robertson, P.K.; Brachman, R.W.I. 2002: Estimating Liquefaction-Induced Ground Settlements from CPT for Level Ground. Canadian Geotechnical Journal, vol. 39, p Limitations i. We have prepared this report in accordance with the brief as provided. This report has been prepared for the use Harker Underground Construction Ltd (on behalf of IAG (NZ) Ltd), their professional advisers and the relevant Territorial Authorities in relation to the specified project brief described in this report. liability is accepted for the use of any part of the report for any other purpose or by any other person or entity. ii. iii. The recommendations in this report are based on the ground conditions indicated from published sources, site inspections and subsurface investigations described in this report based on accepted normal methods of site investigations. Only a limited amount of information has been collected to meet the specific financial and technical requirements of the Client s brief and this report does not purport to completely describe all the site characteristics and properties. The nature and continuity of the ground between test locations has been inferred using experience and judgement and it must be appreciated that actual conditions could vary from the assumed model. Subsurface conditions relevant to construction works should be assessed by contractors who can make their own interpretation of the factual data provided. They should perform any additional tests as necessary for their own purposes. Geoscience ref.: February 2013

9 Geotechnical Assessment for Repair 32 Chapter Street, Saint Albans, Christchurch iv. This Limitation should be read in conjunction with the IPENZ/ACENZ Standard Terms of Engagement. v. This report is not to be reproduced either wholly or in part without our prior written permission. We further note that some of the data included in this report was extracted from the Canterbury Geotechnical Database ( which were prepared and/or compiled for the Earthquake Commission (EQC) to assist in assessing insurance claims made under the Earthquake Commission Act The source maps and data were not intended for any other purpose. EQC and its engineers, Tonkin & Taylor, have no liability for any use of the maps and data or for the consequences of any person relying on them in any way. This "Important notice" must be reproduced wherever this data or any derivatives are reproduced. We trust that this information meets your current requirements. Please do not hesitate to contact the undersigned on if you require any further information. For and on behalf of Geoscience Consulting (NZ) Ltd, Leroy Chan, PE, GE (USA) Project Engineer Greg Martin Associate Engineering Geologist Director Don Bruggers, CPEng, IntPE (NZ); PE, GE (USA) Principal Engineer Attachments: - Site Location Plan - Site Photographs - Hand Auger Borehole Logs - Machine Borehole Log - CPT Liquefaction Analyses (ULS, SLS) Geoscience ref.: February 2013

10 HA01 HA02 MH01 = Test Location te: All images sourced from Google Maps Date Feb-13 Client Harker Underground Construction Ltd Drawn by LC Project Canterbury Recovery Approved by LF Description Site Location Plan Scale NTS Geoscience Ref Client Ref AAD/2

11 Photo 1: rthwest side of dwelling Photo 2: Southwest side of dwelling Photo 3: Southeast side of dwelling Photo 4: Foundation cracking (<5 mm wide) Photo 5: Foundation movement (up to 50 mm) on the southwest side of dwelling Photo 6: Separation in driveway (<50 mm wide) Date taken Jan 2013 Client Harker Underground Construction Ltd Taken by CB Project Canterbury Recovery Approved by LC Description Site Photographs Photo. 1 to 6 Geoscience Ref Client Ref AAD/2

12 HAND AUGER BOREHOLE - HA01 (Page 1 of 2) 32 Chapter Street Saint Albans AAD/2 Client : HUC Ltd Project : Canterbury Recovery Geoscience Ref. : Drilling Method : Hand auger Hole Diameter : 50 mm Date : 30/01/13 Hole Depth : 3.0 m Shear Vane. : Logged By : JCL/AN Reviewed By : JR Depth (m) Material USCS Symbol DESCRIPTION Graphic Log Water Level Moisture Condition Shear Vane (kpa) Peak/Remolded Consistency / Density Index Scala Penetrometer Blows per 100 mm TS SILT with trace sand and rootlets, light brown [TOPSOIL]. FILL SILT with trace gravel, clinker, brick, organics and porcelain; dark brown [FILL]. M 0.5 SILT; light yellowish brown. Becomes wet and greyish brown with orange mottles at 0.7 m depth C:\Documents and Settings\default\My Documents\NZ\ Harker\9835_32 Chapter Street\ _HA01.bor ALLUVIUM Becomes brown at 2.1 m depth. Orange mottling encountered at 2.8 m depth. Becomes saturated at 2.9 m depth. EOH: 3.0 m Termination: Target Depth Hand auger and Scala Penetrometer met target depth at 3.0 m depth. Groundwater encountered at 2.9 m depth. TS = TOPSOIL W S St-VSt F-St VSt

13 HAND AUGER BOREHOLE - HA02 (Page 2 of 2) 32 Chapter Street Saint Albans AAD/2 Client : HUC Ltd Project : Canterbury Recovery Geoscience Ref. : Drilling Method : Hand auger Hole Diameter : 50 mm Date : 31/01/13 Hole Depth : 3.0 m Shear Vane. : Logged By : JCL/EG Reviewed By : JR Depth (m) Material USCS Symbol DESCRIPTION Graphic Log Water Level Moisture Condition Shear Vane (kpa) Peak/Remolded Consistency / Density Index Scala Penetrometer Blows per 100 mm SILT with trace sand, gravel, brick, charcoal and rootlets; dark brown [FILL]. FILL 0.5 SILT; brown. F-VSt C:\Documents and Settings\default\My Documents\NZ\ Harker\9835_32 Chapter Street\ _HA02.bor ALLUVIUM Orange mottling encountered at 0.9 m depth. Becomes wet at 1.7 m depth. EOH: 3.0 m Termination: Target Depth Hand auger and Scala Penetrometer met target depth at 3.0 m depth. Groundwater not encountered. M W S-F St-VSt

14 MACHINE BOREHOLE - MB01 (Page 1 of 2) 32 Chapter Street Saint Albans AAD/2 Client : HUC Ltd Project : Canterbury Recovery Geoscience Ref. : Drilling Method : Rotary Cored Core Diameter : 63 mm Date : 30/01/13 Contractor : Pro-Drill Ltd Hole Depth : m Logged By : JC Reviewed By : JR Depth (m) Material USCS Symbol DESCRIPTION Graphic Log Water Level Moisture Condition Consistency / Density Index TCR (%) SPT N-Value F SM SILT with some gravel and sand; dark brown. Gravel, fine to medium, poorly graded, subrounded to subangular. Sand, fine to coarse, well graded [FILL]. SILT with trace organics; greyish brown with orange mottles. Sandy SILT; greyish brown with orange mottles. Sand, fine, poorly graded. SILT with trace organics; brown. Sandy SILT; greyish brown with orange mottles. Sand, fine, poorly graded. SILT with trace organics; greyish brown with orange mottles. Sandy SILT and trace organics; greyish brown with orange mottles. Sand, fine, poorly graded. SILT with trace organics; greyish brown with orange mottles. Becomes grey with orange mottles at 3.0 m depth. Silty fine to medium SAND; grey; poorly graded. SILT with trace organics; grey. S-F L SPT: 1.5 m 0,0,0,1,1,1 N = mm pen. SPT: 3 m 2,1,2,2,1,1 N = mm pen ALLUVIUM Sandy SILT; grey. Sand, fine, poorly graded. Trace organics encountered from 4.7 m depth. Silty fine SAND with trace organics; grey; poorly graded. F SPT: 4.5 m 1,0,1,1,3,3 N = mm pen SPT: 6 m 2,1,2,2,3,2 N = mm pen. SM SPT: 7.5 m 2,2,0,1,2,2 N = mm pen. 8.5

15 MACHINE BOREHOLE - MB01 (Page 2 of 2) 32 Chapter Street Saint Albans AAD/2 Client : HUC Ltd Project : Canterbury Recovery Geoscience Ref. : Drilling Method : Rotary Cored Core Diameter : 63 mm Date : 30/01/13 Contractor : Pro-Drill Ltd Hole Depth : m Logged By : JC Reviewed By : JR Depth (m) Material USCS Symbol DESCRIPTION Graphic Log Water Level Moisture Condition Consistency / Density Index TCR (%) SPT N-Value Cont. Silty fine SAND with trace organics; grey; poorly graded SM L SPT: 9 m 1,1,1,1,2,3 N = mm pen SILT with some organics; grey. Silty fine SAND with trace organics; grey; poorly graded. F SPT: 10.5 m 1,0,1,2,2,2 N = mm pen SM ALLUVIUM Fine to medium SAND; grey; poorly graded. SPT: 12 m 3,2,3,4,4,4 N = mm pen Some organics and wood encountered at 13.0 m depth. MD SP SPT: 13.5 m 4,6,6,6,6,6 N = mm pen Some silt encountered from 15.0 m depth. EOH: m SPT: 15 m 7,7,7,6,6,7 N = mm pen Termination: Target depth Machine borehole met target depth at m depth. Groundwater recorded at 3.2 m depth after drilling. F = FILL

16 Geoscience Consulting (NZ) Ltd P.O. Box 110 Lyttelton 8841 LIQUEFACTION ANALYSIS REPORT Project title : 32 Chapter Street Location : Saint Albans CPT file : TT CPT Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value G.W.T. (in-situ): G.W.T. (earthq.): Average results interval: Ic cut-off value: Unit weight calculation: Based on SBT Yes Clay like behavior applied: Sands only Limit depth applied: Limit depth: Summary of liquefaction potential CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:45:19 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT ULS.clq 1

17 This software is licensed to: ENGEO Incorporated CPT name: TT CPT Liquefaction analysis overall plots (intermediate results) Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value Depth to GWT (erthq.): Average results interval: Ic cut-off value: Unit weight calculation: Use fill: Fill height: Based on SBT CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:45:19 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT ULS.clq Sands only Yes. 2

18 This software is licensed to: ENGEO Incorporated CPT name: TT CPT Liquefaction analysis overall plots F.S. color scheme Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value Depth to GWT (erthq.): Average results interval: Ic cut-off value: Unit weight calculation: Use fill: Fill height: Based on SBT CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:45:19 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT ULS.clq Sands only Yes. Almost certain it will liquefy Very likely to liquefy LPI color scheme Liquefaction and no liquefaction are equally likely Very high risk Unlike to liquefy High risk Almost certain it will not liquefy Low risk 3

19 Geoscience Consulting (NZ) Ltd P.O. Box 110 Lyttelton 8841 LIQUEFACTION ANALYSIS REPORT Project title : 32 Chapter Street Location : Saint Albans CPT file : TT CPT Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value G.W.T. (in-situ): G.W.T. (earthq.): Average results interval: Ic cut-off value: Unit weight calculation: Based on SBT Yes Clay like behavior applied: Sands only Limit depth applied: Limit depth: Summary of liquefaction potential CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:42:17 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT SLS.clq 1

20 This software is licensed to: ENGEO Incorporated CPT name: TT CPT Liquefaction analysis overall plots (intermediate results) Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value Depth to GWT (erthq.): Average results interval: Ic cut-off value: Unit weight calculation: Use fill: Fill height: Based on SBT CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:42:17 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT SLS.clq Sands only Yes. 2

21 This software is licensed to: ENGEO Incorporated CPT name: TT CPT Liquefaction analysis overall plots F.S. color scheme Input parameters and analysis data I&B (2008) R&W (1998) Based on Ic value Depth to GWT (erthq.): Average results interval: Ic cut-off value: Unit weight calculation: Use fill: Fill height: Based on SBT CLiq v CPT Liquefaction Assessment Software - Report created on: 2/20/2013, 2:42:17 PM Project file: C:\LC\New Zealand\32 Chapter\32 chapter TT SLS.clq Sands only Yes. Almost certain it will liquefy Very likely to liquefy LPI color scheme Liquefaction and no liquefaction are equally likely Very high risk Unlike to liquefy High risk Almost certain it will not liquefy Low risk 3