Testing device for hydraulic fracturing of soil core wall

Abstract

The invention discloses a test device for hydraulic fracturing of a soil core wall, which belongs to the technical field of water conservancy projects and comprises a top cover, a base, a permeable plate, a sample test cavity positioned below the permeable plate, an axial pressure measurement assembly, a pore water pressure assembly and a confining pressure assembly. The top cover, the base and the sample test cavity form a hollow sealing structure, and the pore water pressure assembly is located in the sample test cavity. The confining pressure assembly is located outside the sample test cavity and wraps the sample test cavity. The axial pressure measuring assembly comprises a steel shaft, a damping device and a load sensor located on the damping device. A steel shaft channel is formed inthe top cover, and a steel shaft penetrates through the steel shaft channel to be connected with the damping device. The damping device is located above the center of the water permeable plate and connected with the water permeable plate. The diameter of the permeable plate is equal to that of the sample test cavity. The device can be used for researching the anti-permeability mechanism under thecombined action of the clay and the inverted filter, and can accurately simulate the stress conditions of unequal stress of the core wall clay and the inverted filter.

Description

technical field [0001] The invention relates to a test device for hydraulic splitting of a soil core wall, belonging to the technical field of hydraulic engineering. Background technique [0002] At present, the hydraulic splitting tests of high clay core dams can be divided into laboratory tests, field tests and model tests. Among them, the indoor test generally adopts a cylindrical sample (thick-walled or thin-walled cylinder) or a rectangular parallelepiped sample with a central hole (cylindrical hole) or slit ("envelope"-shaped crack). Water was injected in the middle until the sample was split, so as to discuss the occurrence conditions of hydraulic splitting, the development form of cracks and its influencing factors. Indoor tests are convenient for accurate control of test conditions and have strong repeatability, so they are widely used. [0003] However, the existing laboratory tests of hydraulic splitting of the core wall of earth-rock dams still have the followi...

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Problems solved by technology

[0003] However, the existing laboratory tests of hydraulic splitting of the core wall of earth-rock dams still have the following defects: 1. The clay sample is prone to deformation during the moving process, resulting in a decrease in the strength of the sample or a change in the initial stress state, etc.

2. The core wall sample does not consider the influence of the reverse filter layer, and cannot simulate the joint action of clay and reverse filter

3. The stress state of the core wall material cannot be accurately simulated without considering the unequal stress of the core wall clay and the filter layer

Therefore, these tests cannot truly simulate the characteristics and stress conditions of high-clay core dams

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