A test method for simulating active failure of shield tunnel excavation face

Abstract

The invention discloses a test method for simulating the active damage of a shield tunnel excavation face. The method includes the steps that after filling in a model box is completed, standing is performed for a period of time, and initial readings on micro water-soil pressure monitoring elements on the cutterhead of a model shield machine, a displacement meter monitoring element in soil in frontof the excavation face and a displacement meter monitoring element on the earth surface are recorded; the model shield machine is made close to the hole of the model box; a jacking motor, a cutterhead motor and a spiral excavator motor of the shield machine are turned on at the same time, and the model shield machine starts tunneling; when the model shield machine excavates to a preset position,the jacking motor, the cutterhead motor and the spiral excavator motor are turned off at the same time; a shield excavation face active damage test is started; the water-soil pressure value on the cutterhead, the displacement value of the soil in front of the excavation face and the settling volume of surface soil are recorded, and after standing for a period of time, numerical values of the monitoring elements are measured. In the method, it is taken into account that the early excavation process of the model shield is consistent with the truth of the influence of the early tunneling processon the true active damage of the shield excavation face.

Description

technical field [0001] The invention relates to the field of tunnel engineering, in particular to a test method for simulating the active damage of the excavation surface of a shield tunnel. Background technique [0002] With the pace of development and utilization of urban underground space in my country, major cities in China, especially first-tier cities such as Beijing and Shanghai, have widely adopted the shield method for urban subway construction. However, since the large-diameter shield tunneling project in our country has only gradually developed in recent years, it is still in its infancy both in terms of construction technology and theoretical research. Therefore, there are many deficiencies in the theoretical research on shield tunneling, which need to be studied deeply and systematically by scholars at home and abroad. [0003] Due to the strict requirements on the surrounding buildings, structures and formation deformation of the shield, the requirements for t...

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Problems solved by technology

[0005] There have been many tests in China to simulate the active failure of the excavation surface of the tunnel, but most of them are displacement control, that is, the active failure process of the excavation surface of the tunnel is simulated by the retreat of the support baffle, which is different from the active failure of the excavation surface of the real shield tunnel. The situation does not match

There are also model tests at home and abroad that use the model shield machine to simulate the stability of the excavation surface. However, the model shield machine is generally pre-embedded in the soil, the cutter head is directly rotated to cut the soil, and then the soil is manually unearthed, without considering the model. The pre-excavation process of shield tunneling

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