FEATURES TerraDol provides innovative geotechnical and geophysical exploration for civil construction projects including highway, railroad, subway, tunnel, bridge, port, and underground storage projects. We possess various types of in-situ geotechnical / geophysical testing equipments in house and are able to provide reliable investigative services within reasonable time at a reasonable cost. In-Situ test In-situ load test (LLT, PMT, GMJ) In-situ shear test Cone penetration test Plat load test Field vane test Pumping test In-situ permeability test Water flow test Hydraulic fracturing test Full wave sonic test Borehole image processing survey (OPTV) Borehole televiewer survey (BHTV) Geophysical exploration Refraction, reflection seismic survey Resistivity survey Electro-Magnetic survey (MT, TEM) Very low frequency survey Multi analysis surface wave (MASW) Ground penetrating Radar (GPR) Cross borehole test Tomography survey Resistivity GPR Survey In-situ load Test test Cone penetration test test Regional geological exploration Geological ground survey Aerial and satellite photograph 3D-scanner Plat load test Borehole televiewersurvey Geological ground survey Satellite photograph Experienced Experts Cutting edge Technology Up-to-date Equipments Plentiful Experience Research & Development
BOREHOLE GEOPHYSICAL INVESTIGATION CHT (Cross Hole Test) & DHT (Down Hole Test) The seismic crosshole test provides dynamic subsurface properties by determining wave velocities. Seismic waves are generated in a source borehole and recorded in a receiver borehole (CHT) or at the surface (CHT). The measurements can be performed below and above the groundwater table. These tests are mainly applied for the investigation of construction sites. The test methodology is described in ASTM 4428. Borehole Televiewer Borehole televiewer logging is used to obtain oriented images of borehole cores by acoustic signal (Acoustic Televiewer) or high resolution digital image (Optical Televiewer). These methods utilize a built in fluxgate magnetometer to orient the image with respect to magnetic north. The output data provides unique ability to present the core either as a wrapped image, looking out from the center of the borehole. Analysis of the data allows void and joint data to be presented in terms of depth, dip direction, dip angle, and strike. Test results Optical televiewer Acoustic televiewer Suspension PS Logging The Suspension PS logging is used to measure P and S wave velocities that propagate through formation by means of an indirect excitation source and a pair of non-clamping geophones and hydrophones built into one downhole tool suspended in a borehole. This system is best suitable for the exploration in a deep hole or at offshore where the plate hamming method is not effective. CHT diagram DHT diagram Resistivity Logging Resistivity logging is used to characterize rock or sediment in a borehole by measuring electrical resistivity. The electric resistivity is measured using four electrical probes to eliminate the resistance of the contact leads. The log must run in holes containing electrically conductive mud or water. Logging diagram Test results Test results
SURFACE GEOPHYSICAL INVESTIGATION Ground Penetrating Radar (GPR) Ground-penetrating radar (GPR) survey uses radar pulses to image the subsurface condition. GPR can be used in a variety of media such as rock, soil, ice, fresh water, pavements and structures. It can detect objects, changes in material, and voids and cracks. Electrical Resistivity Survey Electrical resistivity is a geophysical technique for imaging subsurface structures by measuring electrical resistivity at the surface or by electrodes in one or more boreholes. 3D survey result 2D survey result 3D result sections Seismic Reflection Survey Seismic reflection follows the law of mirror images the angle of reflection from a surface is equal to the angle of incidence. Seismic Refraction Survey Seismic refraction survey is used to determine rock competence for engineering application such as depth to bedrock, groundwater exploration, crustal structure and tectonics. Traveltime curves Test result Interpretation section Seismic tomography Seismic tomography is a technique for imaging subsurface characteristics to identify and understand deep geologic structures. Measurement of ample compression wave (Pwave) and shear wave (S-wave) travel times enable to compile 3D images of subsurface velocity structures. Multi-channel Analysis of Surface Waves (MASW) MASW method is for evaluating the elastic stiffness of the ground by measuring shear-wave velocity (V s ) which is one of the elastic constants and closely related to Young s modulus of the material. The shear-wave velocity (V s ) is a direct indicator of the ground strength (stiffness) and commonly used to derive load-bearing capacity. Raw data & picking Seismic tomography result section Dispersion curves Shear-wave result section
IN-SITU TESTS Standard Penetration Test (SPT) energy calibration SPT Energy Calibration consists of measuring the energy transferred by the Standard Penetration Test (SPT) hammer to the SPT rod. SPT energy calibration improves the reliability of the standard penetration test. Cone Penetration Test (CPT) The cone penetration test is used to determine geotechnical engineering properties of soils and delineating soil stratigraphy. Test diagram Hydraulic fracturing test Hydraulic fracturing is to determine the maximum principal stress direction and to measure the coefficient of lateral stress by pumping fluid into a borehole at an injection rate and the fluid pressure is to fracture rocks. Application of test result Field vane test The field vane test is the most widely used method for estimation of the in-situ undrained shear strength of soft clays. The test is carried out with a rectangular vane, consisting of four plates, pushed into the soil to the desired depth and rotated. Test diagram Test mimetic diagram Application of test result
IN-SITU TESTS Pumping test A pumping test is a controlled field experiment in which a well is pumped at a controlled rate and water-level response is measured in one or more surrounding observation wells and optionally in the pumped well itself. Borehole Packer (Lugeon) test Borehole packer test is widely used to estimate average hydraulic conductivity of rock mass. Depth(m) K(cm/sec) Infiltration test Infiltration test is to measurement horizontal permeability in soft clay layer. Rain intensity(mm/hr) Flowmeter test Field permeability test Field permeability test enables rapid comparisons of rates of moisture infiltration through soil layer or soil horizons. Detected in the four directions of groundwater flow, the flowmeter test determines flow direction and flow velocity. Test diagram Test diagram
GEOLOGICAL TESTS Satellite image analysis & DEM analysis Satellite image analysis & DEM analysis characterize the regional terrain and analyze the development state of the macro-structure. They use faults and terrain analysis to investigate the discontinuity attitude. Aero photo analysis Aero photo analysis allows cameras that are installed on the aircraft to shoot surfaces vertically. They can analyze geological features such as mainstream, tributary, valley, permeability of the stream, and erosion resistance. Satellite image analysis DEM analysis Aero photo diagram Aero photo 3D scanner 3D Scanner can determine the slope strike, dip, and direction joint. It measures displacement of the dam and pier slope and secures 3D data in the main facility. Laser/Receiver Time Measurement Strike & dip analysis Length analysis Mirror Object Geological survey A geological survey is a systematic investigation that uses satellite images and DEM to analyze lineament and mechanical properties of the discontinuity. It identifies discontinuity spacing, length and attitude. Survey diagram Joint analysis Modal analysis Geological map Survey result
EQUIPMENT & SOFTWARES Item Quantity Manufactured in 1 TERRALOC PRO 2 set ABEM (Sweden) 2 TERRAMETER LS ABEM (Sweden) 3 RAMAC/GPR Mala Geoscience (Sweden) 4 5 Seismic Tomography: P-wave Sparke/SH-wave Sparker Hydrophone 24ch/3C Borehole Geophone 7C Borehole Geophone MT (Imagem / Stratagem) ZHF (High Frequency Electro Magnetic) each 2 set Geotomographie(Germany) Geostuff (USA) Geotomographie(Germany) EMI (USA) 6 Borehole Optical Televiewer RG (UK) 7 Borehole Acoustic Televiewer RG (UK) 8 Suspension PS Logger probe RG (UK) 9 FDGT sonde Small-source density sonde RG (UK) 10 Borehole Shear Tester Handy Instrument (USA) 11 SPT Analyzer PDI (USA) 12 SISSY(Seismic Impulse Source System) RUAG (Germany) 13 Borehole Electrode 2 set Geotomographie (Germany) 14 Geophones - 4.0Hz ~ 100Hz 25 ea GISCO (USA) / Geospace (USA) 15 VLF/WADI ABEM (Sweden) 16 SASLog200 ABEM (Sweden) 17 Hermit SE2000 8channel Hermit (USA) 18 ph Meter Hermit (USA) 19 Conductivity Meter Hermit (USA) 20 SEBA Hydrometric D-8950 SEBA (USA) 21 ReflexW2D/3D Geotomographie (Germany) 22 SeisImager OYO (Japan) 23 Geo CT-II GeoTomo (USA) 24 SurfSeis KGS (USA) 25 Res2DInv Geotomo software (Malaysia) 26 SensInv2D3D Geotomographie (Germany) 27 DiPro KIGAM (Korea) 28 Gradix Interpex (USA) 29 Easy 3D Mala Geoscience (Sweden) 30 Ground Vision Mala Geoscience (Sweden) 31 Ramag VLF ABEM (Sweden) 32 TomTime / Geo TomCG 33 RGLDIP -HIRAT -Doptv GeoTom LLC (USA) 34 Well-CAD - RG (UK)
WATER TUNNEL PROJECT EXAMPLE
CASE HISTORY: DETECTION OF SUBSURFACE OBSTACLES