A disaster mitigation method for uneven ground fissure settlement deformation based on rigid isolation walls: A case study in Beijing Capital International Airport ground fissure

With the continuous expansion of urban construction land and the development and utilization of underground space, the conflict between ground fissures, which are widely developed in urban areas, and urban construction has become increasingly prominent. It has become a particularly prominent geological problem in urban construction, seriously affecting the planned construction of urban buildings and the safe service of the entire life cycle of existing infrastructure. Based on the principle of limit equilibrium, the calculation formulas of soil pressure, internal force and lateral displacement of the isolation wall are derived, and the variation laws of soil pressure and lateral displacement of the isolation wall under different wall parameters and soil parameters are analyzed, and the applicability of the theoretical formula was verified through numerical simulation. On this basis, taking the ground fissures site of Beijing Capital International Airport as an example, and a disaster mitigation method for Beijing Capital International Airport ground fissure settlement deformation based on rigid isolation walls was proposed. Research shows that the soil pressure of the isolation wall above the intersection point of the ground fissure and the isolation wall is distributed in a triangular pattern, and below the intersection point, it is distributed in a trapezoidal pattern, the analytical solution and the numerical solution have the same changing trend, the soil pressure at any depth obtained by the analytical solution is always greater than that of the numerical solution, which is approximately 1.11 times. With the increase of the thickness of isolation wall, the soil pressure of isolation wall gradually increases and the lateral displacement gradually decreases. When the wall thickness increases from 0.5m to 1.5m, the maximum soil pressure value increases by 5.62% and the lateral displacement at the top decreases by 8.62%, at the bottom increases by 22.7%. When the wall thickness increased from 1.5 m to 2.5 m, the maximum soil pressure decreased by 1.16%, the lateral displacement at the top increased by 4.3%, and the lateral displacement at the bottom decreased by 15%. The soil pressure and lateral displacement of the isolation wall gradually decrease with the increase of the elastic modulus and Poisson's ratio of the soil, when the elastic modulus of the soil increases by 1.2 times, the soil pressure exerted on the retaining wall decreases by 42.02%, when the Poisson's ratio of the soil increases 0.05, the soil pressure exerted on the retaining wall decreases by 29.3%. The soil pressure and lateral displacement of the isolation wall are minimally affected by the elastic modulus of the wall, only about 1%. The disaster mitigation method based on the uneven settlement deformation of ground fissures caused by isolation wall can alleviate the ground fissures disaster at Beijing International Airport, with the increase in the active dislocation amount of ground fissures, the soil pressure, lateral displacement and bending moment of the isolation wall increase. The research results will deepen the understanding of the disaster reduction mechanism of ground fissures and provide theoretical support for the design of ground fissures disaster reduction and prevention.