Water-force coupling test method for tunnel surrounding rock and lining structure bearing system

Abstract

The invention discloses a water-force coupling test method for a tunnel surrounding rock and lining structure bearing system. The method comprises the following steps of pouring a lining structure and a surrounding rock layer which have the same height and flush end surfaces; installing an equal surrounding rock pressure steel strand prestress loading mechanism, vertically hoisting a whole body formed by the lining structure and the surrounding rock layer together with a prestressed steel strand which is wound around the periphery of the surrounding rock layer and with two ends connected into the inner cavity of a reaction wall; installing and sealing the upper cover plate; installing an external water pressure loading mechanism; loading external water pressure; and conducting data acquisition, and conducting acquisition and post-processing on acquired data such as stress strain, prestress of the steel strand applying surrounding rock pressure, the external water pressure and the like through data acquisition software. According to the water-force coupling test method, the stress characteristics and related deformation characteristics of the tunnel surrounding rock and a water delivery tunnel lining structure under the action of complex external loads and equal surrounding rock pressure in the actual environment can be simulated, and the failure form of the lining structure and crack distribution after cracking can be analyzed and researched.

Description

technical field [0001] The invention relates to the technical field of test structure models of long-distance water conveyance tunnels, in particular to a hydraulic-mechanical coupling test method for the bearing system of a tunnel surrounding rock and a lining structure. Background technique [0002] There are more and more long-distance water supply projects. The water diversion tunnels are often located in high mountains and valleys, with large deep burials and high in-situ stress. During the operation of the tunnels, the surrounding rock-lining structure will bear large external water pressure and surrounding rock pressure. The existence of high external water pressure in tunnels often leads to engineering accidents such as large-scale landslides, water inrush, and lining rupture during construction and operation. The surrounding rock pressure of the tunnel is divided into top pressure, side pressure and bottom pressure according to the direction of pressure. Some tunnel...

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Problems solved by technology

[0003] It is very important to find an effective hydraulic-mechanical coupling test method for equal surrounding rock pressure and high-altitude underwater joint bearing. The current water tunnel test method has certain disadvantages: First, the stability and stability of the water tunnel test device The tightness often fails 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 well reflect the stress characteristics and related deformation characteristics of the surrounding rock-lining structure under actual complex loads. Therefore, it is not easy to study the damage pattern of the lining structure and the distribution of cracks after cracking; secondly, the existing surrounding rock layer is mostly poured with ordinary concrete, which cannot reflect the crack distribution of the real surrounding rock structure, and even if it is loaded to the required The external water pressure 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 by external water pressure to act directly The surrounding rock pressure is loaded on the lining structure, which is inconsistent with the actual load bearing method of the lining

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