Multi-point in-situ stress test method of soft rock using connecting rod

Abstract

The invention discloses a soft rock multi-measuring-point ground stress testing method by using a connecting rod. During working, a plurality of groups of three-way pressure boxes (each group has two pressure boxes) are closely fixed on the connecting rod by using locking screws and multiple connecting rod sections are sequentially installed and operated till all measuring point three-way pressure boxes are pushed to a design position; the connecting rod is also used as a grouting pipe, full-hole grouting is performed, the stress to the three-way pressure boxes is measured and resolved to obtain stress components Sigma'(x), Sigma'(y), Sigma'(z), Tau'(xy), Tau'(yz) and Tau'(zx) of each pair of three-way pressure boxes at positions in a hole under a drill hole local coordinate system, then a cylindrical double-medium mechanical model is established, and stress components Sigma (x), Sigma (y), Sigma (z), Tau (xy), Tau (yz) and Tau (zx) of an in-situ stress field of the position of the drill hole are obtained by adopting a numerical simulation method through iterative convergence. Since the connecting rod used in the method is also used as the grouting pipe, uniform grouting is realized, grout mediums in the hole are uniform and the calculation is simpler and more convenient to perform; the ground stress values of multiple measuring points in deep soft rock can be directly measured and the continuous monitoring of the ground stress is realized.

Description

technical field [0001] The invention belongs to the technical field of geotechnical measurement, and in particular relates to a multi-measuring point in-situ stress testing method of soft rock using connecting rods. Background technique [0002] The safe construction of deep mine tunnels depends on the understanding of the spatial distribution and time evolution of the in-situ stress field. In the deep broken and weak surrounding rock in coal mines, it is very difficult to effectively test the in-situ stress by using the current commonly used test methods. The hydraulic fracturing method widely used in hard rock requires good water tightness under high water pressure for its borehole packer, which imposes strict requirements on the integrity of the rock mass, and is especially not suitable for deep joints in coal mines. Broken and weak rock mass with developed fissures. Another common test method is the stress relief method. Because it is difficult to obtain the core in t...

AI Technical Summary

Problems solved by technology

Due to the difficulty of obtaining cores in soft surrounding rocks in deep coal mines, the mechanical parameters cannot be obtained through uniaxial compression experiments, and the stress relief method is difficult to implement in broken and weak rock masses

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