Test method for simulating expansive surrounding rock tunnel rainfall infiltration

Abstract

The invention discloses a test method for simulating expansive surrounding rock tunnel rainfall infiltration. The test method includes the steps that step1, a test device for simulating expansive surrounding rock tunnel physical model rainfall infiltration is established, wherein the test device comprises a water diversion flow-guiding system portion and a model casing portion, the water diversion flow-guiding system portion is installed on the upper portion of the model casing portion, and the water diversion flow-guiding system portion and the model casing port are connected through metal pipes with small holes in pipe walls; step2, a water-containing bottle contains water used for simulating rainfall, the water flows into a flow-distributing device from the water-containing bottle through a master flow-guiding pipe and is divided into 12 branches of water through the flow-distributing device, all the branches of water flow into the metal pipes with the small holes in the pipe walls through flow-guiding water-distributing pipes, and the points of the metal pipes are inserted into rock mass by 10 cm-15 cm; because the water inside the pipes has certain head pressure, the water inside the metal pipes is pressed into the rock mass through the pressure, and when air enters the flow-guiding water-distributing pipes and causes unsmooth water flowing, the air inside the pipes is exhausted through exhaust valves to keep smooth water flowing. The device is simple in structure, and the effects that the water is guided into the rock mass, water of surrounding rock is distributed evenly, and the rainfall per unit time can be effectively controlled can be achieved.

Description

technical field [0001] The invention relates to a test method in the field of expansive surrounding rock tunnels, in particular to a test method for simulating rainfall infiltration in expansive surrounding rock tunnels. Background technique [0002] Expansive rock and soil is a kind of rock and soil with significant expansion and contraction characteristics, which is multi-cracked, swells and softens when exposed to water, shrinks and cracks when it loses water. When the tunnel passes through the special geological body of expansive rock and soil, this undesirable characteristic is often caused by atmospheric rainfall infiltration and natural air drying and evaporation, causing serious damage to the tunnel structure. [0003] At present, there are few studies on rainfall infiltration in the physical model of tunnels with expansive surrounding rocks, and the methods and methods of indoor simulation of atmospheric rainfall infiltration are relatively common. Generally, artifi...

AI Technical Summary

Problems solved by technology

[0003] At present, there are few studies on rainfall infiltration in the physical model of tunnels with expansive surrounding rocks, and the methods and methods of indoor simulation of atmospheric rainfall infiltration are relatively common. Generally, artificial watering or irrigation is used to simulate the surrounding rocks. Atmospheric rainfall

In the process of simulating rainfall infiltration, most of the water flows directly out of the box along the side walls of the model box, resulting in poor rainfall infiltration effect.

Moreover, the water cannot be evenly dispersed in the surrounding rock during the rainfall process, which often causes a large difference in the water content of the surrounding rock in different regions, resulting in a far difference from the actual rainfall situation.

In addition, when the model test has specific requirements on the rainfall per unit time, it cannot effectively control the water flow and velocity per unit time.

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