In-hole shear wave source and method for testing wave speed by using cross-hole method

Abstract

The invention relates to an in-hole shear wave source and a method for testing the wave speed by using a cross-hole method. The in-hole shear wave source includes a guide cylinder, a weight, a hammerpad and a trigger. Stopping devices are arranged in the guide cylinder and on the weight. An anti-rotation steel wire rope is arranged at the top of the weight. The method comprises the steps of constructing a receiving hole and an exciting hole, tightly contacting the hammer pad with the bottom of the exciting hole, and calculating the propagation speed of the shear wave. The trigger is installedon the top of the weight and ensures accurate triggering time. The test method is good in adaptability, can be used for drilling rock or soil texture. Large shock excitation energy, strong effectivesignals, and far effective propagation distance of the shear wave are achieved.

Description

technical field [0001] The invention relates to a shear wave seismic source in a hole and a wave velocity testing method of a cross-hole method, belonging to the field of engineering technology. Background technique [0002] The cross-hole wave velocity test is an important means to test the shear wave velocity, compression wave velocity, dynamic shear modulus, dynamic elastic modulus and dynamic Poisson's ratio of rock and soil in geotechnical engineering investigation. The in-hole seismic source is a key equipment for the cross-hole wave velocity test. The following two types of equipment are usually used. One is a hydraulic wall-supported shear hammer, which has a large supporting force in the hole, but the travel of the support plate is limited. Rock drilling and soil drilling cannot be reliably adhered to the wall; the other is the airbag wall-attached shear hammer. Although it is applicable to a wide range of apertures, it is difficult and easy to inflate the airbag in...

AI Technical Summary

Problems solved by technology

The in-hole seismic source is a key equipment for the cross-hole wave velocity test. The following two types of equipment are usually used. One is a hydraulic wall-supported shear hammer, which has a large supporting force in the hole, but the travel of the support plate is limited. Rock drilling and soil drilling cannot be reliably adhered to the wall; the other is the airbag wall-attached shear hammer. Although it is applicable to a wide range of apertures, it is difficult and easy to inflate the airbag in drilling holes with well fluid. air leak problem

Both have the problem of small excitation energy. When the drilling distance is large or the elastic modulus of rock and soil is large, and large excitation energy is required, the requirements are often not met.

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