Crosshole Test (CHT)
Definition - What does Crosshole Test (CHT) mean?
A crosshole test (CHT) is performed to determine the shear wave velocity of soils to measure its stiffness. The crosshole test is conducted for site investigation and characterization of material in soil deposits or rock formations, and the data is used to obtain a detailed in-situ seismic wave velocity profile. The CHT is conducted near the surface (the upper hundred meters) and determines the compressional and shear wave velocity of materials.
Trenchlesspedia explains Crosshole Test (CHT)
Crosshole testing can assess soil properties that are not determinable from cone penetration testing (CPT) and works as a complimentary data to CPT especially in determining the effectiveness of construction done for ground improvement.
The CHT test is performed using two special probes placed approx. 1.5 meter apart, that are pushed into the soil vertically and parallel to each other using hydraulic rams. The probes are mounted at the tip of a rod string and measure the shear wave velocity between them. The shear wave generation is done by striking the push rods with hammers.
One probe behaves as the shear wave emitter while the other receives the waves generated by the first probe.