Boring elastic modulus instrument with flexible carrying plate

Abstract

The invention provides a boring elastic modulus instrument with a flexible carrying plate. The boring elastic modulus instrument comprises a hydraulic loading device, a carrying plate, a displacement sensor and a pressure transmitting block, wherein the upper part of the hydraulic loading device is sequentially provided with the pressure transmitting block and the carrying plate, the carrying plate is a flexible carrying plate made of materials with the elastic modulus being 1 to 5GPa, the surface of the carrying plate is in an arc shape and is arranged in a carrying plate groove formed in the pressure transmitting block, resin glue and a stud are adopted between the carrying plate and the carrying plate groove for positioning, the peripheries are not in contact, and in addition, the bottom of the carrying plate is 1.5 to 2.5mm higher than the outer surface of the carrying plate groove. The contact condition of the instruments and the hole wall of a drill hole in the test process can be improved, so the carrying plate realizes the sufficient contact with the rock hole wall, and the uniform distribution pressure is provided.

Description

technical field [0001] The invention relates to the field of geotechnical engineering and is suitable for measuring the elastic modulus of different depths of boreholes, especially for measuring the elastic modulus of layered rock mass in different directions. Background technique [0002] The elastic modulus of rock mass is an important parameter in geotechnical engineering design. At present, the elastic modulus of the rock mass is generally determined through laboratory tests. However, due to the complexity of the rock mass structure and the diversity of rock components, the elastic model of the rock mass on site is quite different from the value determined by the laboratory test, and it must be tested on site. to provide reliable parameters. Therefore, it is of great significance to study and design the equipment for measuring the elastic modulus of rock mass on site to understand the geological state of geotechnical engineering and guide the construction design. [00...

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Problems solved by technology

There are two types of existing drilling modulus instruments. One is to use "capsule" loading to uniformly load the borehole wall. The measured results are the average value of the elastic modulus in each direction. The representative one is the Canadian Roctest company. The developed Probex drilling modulus instrument; the other is to use a curved strip-shaped rigid loading plate for loading, which can measure the elastic modulus in different directions of the drilling, because most rock masses show anisotropy characteristics, so this This method is more practical, but in the test of this type of elastograph, only a small part of the rigid loading plate is in contact with the surrounding rock (see the appendix for analysis), and the contact area changes with the loading stress, which is inconsistent with the theoretical analysis assumptions, resulting in The calculated result is quite different from the actual elastic modulus of the rock mass. At the same time, the displacement sensors of this type of elastic modulus instrument are located at both ends of the equipment. Due to the bending deformation of the loading plate during the test, the measured displacement is larger than the deformation of the rock mass. The elastic modulus of the rock mass calculated by this method is relatively small. In view of the above reasons, the academic and engineering circles have great disputes about the test results of this type of elastic modulus instrument.

Therefore, the structure of the existing elastometer cannot meet the testing requirements of geotechnical engineering

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