Model test device for simulating influence of excavation of double underground diaphragm wall foundation pits on converging deformation of tunnel

Abstract

The invention relates to a model test device for simulating the influence of the excavation of double underground diaphragm wall foundation pits on the converging deformation of a tunnel. The top surface of a model box is arranged to be open, and a tunnel lining model is placed in a soil body in the model box and is parallel to the short edges of the model box; an underground diaphragm wall model is placed on the right side of the model box; transverse supporting models are fixed in the underground diaphragm wall model; a foundation pit bottom plate model is fixed to the bottom of each foundation pit; infrared distance measurement devices are fixed to the inner wall of the tunnel lining model, and every two infrared distance measurement devices are paired; and the infrared distance measurement devices are embedded in the tunnel lining model through wires, connected to an infrared distance measurement output system and used for guiding out the accurate converging deformation condition of a measurement point in real time. By the adoption of the model testing device, the influence of the construction of the double underground diaphragm wall foundation pits on the converging deformation of the tunnel nearby can be simulated conveniently and effectively, and certain theoretical reference is provided for making foundation pit construction technical standards and taking safety protection measures for existing underground structures nearby.

Description

technical field [0001] The invention relates to a foundation pit project in the development of urban underground space and underground construction engineering, in particular to a model test device for the effect of the excavation mode of a foundation pit with double ground connecting walls on the convergence deformation of adjacent tunnels. Background technique [0002] Foundation pit construction will affect adjacent underground structures, especially in soft soil areas such as Shanghai. During the construction process, tunnels and surrounding underground structures should be the key protection objects. At present, in order to improve the impact of foundation pit excavation on adjacent tunnels, many projects adopt the method of section excavation. On the side of the foundation pit close to the tunnel, a small foundation pit is divided and excavated in partitions to form a working condition of double underground diaphragm walls on the tunnel side. At present, there are few...

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Problems solved by technology

The theoretical analysis method uses the theory of elasticity and simplifies the research model through assumptions, but to a certain extent, it cannot accurately consider the complex relationship between the foundation pit and the soil; the numerical simulation method generally requires the use of large-scale commercial software, and the establishment of the numerical model is relatively complicated and time-consuming calculation

In addition, due to the limitations of geotechnical testing equipment, it is difficult to obtain accurate soil physical and mechanical parameters, and changes in soil parameters have a great impact on numerical simulation results, so it is easy to cause deviations in calculation results

The field monitoring method is one of the means to obtain the settlement of the surrounding strata during the excavation of the foundation pit. However, due to the limitations of instruments and equipment and human observation factors, the field test results have certain deviations.

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