Method for testing surrounding rock and lining structure under unequal confining pressure and water pressure

Abstract

The invention discloses a method for testing surrounding rock and lining structures under unequal confining pressure and water pressure. The method comprises the following steps that a lining structure and a surrounding rock layer which are the same in height and flush in end face are poured, and a steel strand hole channel is reserved; unequal surrounding rock pressure steel strand prestress loading mechanisms are mounted; the whole formed by the lining structure and the surrounding rock layer and the prestressed steel strand are vertically hoisted into an inner cavity of a reaction wall; the upper cover plate is mounted and sealed; an external water pressure loading mechanism is mounted; an internal water pressure loading mechanism is mounted; the external water pressure is loaded; the internal water pressure is loaded; and the led-out monitoring instrument data line is connected to a data acquisition instrument for data acquisition and post-processing. The method can simulate the stress characteristics and related deformation characteristics of the tunnel surrounding rock and the water delivery tunnel lining structure under complex internal and external loads and unequal surrounding rock pressure in an actual environment, and can analyze and research the failure form of the lining structure and the crack distribution after cracking.

Description

technical field [0001] The invention relates to the technical field of test structure models of long-distance water delivery tunnels, in particular to a test method for surrounding rock and lining structures under unequal confining pressure and water pressure. Background technique [0002] With the continuous improvement of the country's comprehensive national strength, the country's infrastructure construction has developed rapidly. Deep-buried long tunnels continue to emerge in the construction of large-scale underground projects in China. During the construction process, the underground space is affected by the excavation, and the excavation of the project destroys the balance of the original initial stress of the rock mass, resulting in a series of complex tunnels. rock mechanics. On the one hand, the natural equilibrium state of the rock mass is affected by the excavation to produce cracks in the rock mass, and the rock mass around the tunnel will continue to loosen an...

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Problems solved by technology

At present, most of the mechanical monitoring tests for water conveyance tunnels are carried out by numerical simulation methods, and it is difficult to simulate the stress of the surrounding rock of the tunnel and the lining structure of the water conveyance tunnel in the actual environment.

[0004] Although there are some simulation test methods, there are certain disadvantages: First, the stability and sealing of the test device often fail to meet the design requirements, which makes it difficult to load the external water pressure or surrounding rock pressure to the required value, and cannot be well tested. It reflects the stress characteristics and related deformation characteristics of the surrounding rock-lining structure under actual complex loads, so it is not easy to conduct research on the damage pattern of the lining structure and the distribution of cracks after cracking; Concrete pouring cannot reflect the crack distribution of the real surrounding rock structure, and even if it is loaded to the required external water pressure, it cannot simulate the water seepage characteristics of the real surrounding rock structure, and the water pressure cannot be well transmitted to the lining structure, resulting in test errors; Third, some existing test methods use the method of simulating the surrounding rock pressure with external water pressure to directly act on the lining structure to load the surrounding rock pressure, which is inconsistent with the actual load bearing method of the lining

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