Estimation Method of Mechanical Response of Built Tunnel Induced by Dewatering Excavation in Water-rich Stratum

Abstract

The invention provides a simplified estimation method for the mechanical response of adjacent built tunnels induced by dewatering and excavation of foundation pits in water-rich strata. rationalized assumptions and simplifications; understand the engineering background and hydrogeological conditions, and determine the values ​​of the required parameters; calculate the vertical effective stress increment at the position adjacent to the axis of the built tunnel induced by the excavation of the foundation pit in the water-rich stratum; stress and horizontal stress, total horizontal stress and total vertical stress; establish the mechanical equilibrium differential equation of the total horizontal stress and total vertical stress induced by the excavation of foundation pit in water-rich strata adjacent to the existing tunnel; solve the adjacent existing tunnel The additional horizontal displacement axial distribution function of the tunnel under the total horizontal stress induced by the excavation of the excavation of the foundation pit in the water-rich stratum The additional vertical displacement axial distribution function under the total vertical stress; Axial distribution function of additional internal force under the action of total stress induced by dewatering excavation of foundation pit.

Description

technical field [0001] The invention relates to the field of geotechnical engineering, in particular to a simplified estimation method for the mechanical response of adjacent built tunnels that may be induced during the dewatering and excavation of a foundation pit in a water-rich stratum. Background technique [0002] With the in-depth development and utilization of urban underground space, there are more and more foundation pit projects adjacent to the existing subway tunnels. According to statistics, the number of foundation pit projects adjacent to the built subway tunnels in Hangzhou has exceeded 100. Excavation of foundation pits will inevitably disturb the stratum, thereby changing the initial stress field and displacement field in the stratum. Unreasonable enclosure structures or construction methods may lead to uneven heave or expansion of segment joints in adjacent existing tunnels. In severe cases, it may even affect the operational safety and long-term service pe...

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Problems solved by technology

[0004] However, most of the above research results did not consider the effect of foundation pit precipitation on the mechanical response of adjacent built tunnels, so they are not suitable for predicting the mechanical response of adjacent built tunnels induced by foundation pit precipitation excavation in water-rich strata. effect, the calculation process is too complicated, and its practicability and accuracy need to be further verified and discussed

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