• Field Exploration
• Laboratory Testing
• Engineering & Geological Analysis

This consists of soil sampling and rock coring and is carried out by our experienced personnel utilizing truck and ATV-mounted drilling rigs. HJA currently maintains the following rigs for subsurface investigations:

• Mounted on trucks
  • Mobile B-30
  • Mobile B-57
  • Mobile B-80
• Mounted on a GEMCO mud buggy
  • B-53

Cohesive soils can be sampled using 1 to 4 inch diameter Shelby tubes, Dennison Barrels, or California samplers. Granular materials can be evaluated in place using split-spoons in conjunction with the Standard Penetration Test. In place characteristics of soil can also be evaluated using Field Vane Shear Tests.

Rock Materials can be sampled using 1 to 6 inch diameter (ADCDMA sized) core barrels that use either air or water to cool the core bit and flush the hole cuttings. HJA can penetrate rock using carbide and diamond set bits. TxDOT Cone Penetrometer Tests are also used to evaluate the in-place capacity of limestone, shale, and sandstone.

Ground water conditions can be evaluated using 4 to 6 inch diameter piezometers. HJA maintains the ability to conduct drawdown tests to evaluate ground water recharge and pumping capacity. HJA operates a down-hole camera for evaluating the amount and orientation of faults and cracks within rock layers.

HJA maintains an in-house laboratory that operates in general compliance with ASTM E329 and is capable of performing a wide range of soil and rock testing.

Equipments used in developing test data are automatic liquid limit devices, direct shear machines, consolidometers with load ratios of 1:1, 6:1, and 10:1, a load frame manufactured by ELE/Soiltest capable of unconfined and Tri-Axial compression testing. HJA is capable of performing Brazilian tensile testing, double ring shear, and Hoek Cell testing of rock core samples on either the ELE/Soiltest load frame or a TestMark compression machine.

In the field, HJA can provide relative elevation surveys using transits and self-contained water levels. Movements of large slopes and deep excavations can be monitored using HJA owned inclinometers manufactured by Slope Indicator.

HJA has all the capabilities to perform field CBR and Plate Load tests.

Licensed engineers and experienced geologists are currently on-staff at HJA to conduct geotechnical studies and geological assessments. These assessments include reports for high-rise construction with deep excavations into rock and normally consolidated soils; studies for repair of existing and construction of new earth dams; evaluation of subsurface conditions for new water transmission pipelines, rock wall stability for deep excavations and stability studies for soil and rock slopes.

Software used in our analysis include proprietary spreadsheets, GSTABL7 (June 2003) for slope stability analysis, SNAIL by Caltrans for soil nail wall design and analysis, L-Pile for evaluating lateral loads on drilled shafts, Retain Pro 6 for design and evaluation of concrete and masonry retaining walls, and Grapher by Golden Software for developing graphical presentations of field data and laboratory test results.

Test data gathered from the field during exploration and as a result of the laboratory testing program are reduced and analyzed by experienced personnel. Results and recommendations are compiled in formal style reports, which are peer-reviewed by the Principal Engineer prior to issuance.