Study on the structural response of surrounding buildings during tunnel excavation in urban areas

This study, based on the Guanzhong Road tunnel project in the core urban area of Chongqing, systematically investigates the influence of tunnel excavation on adjacent building structures by establishing a tunnel-building interaction numerical model. A two-dimensional plane strain model was developed using MIDAS/GTS software, focusing on the response mechanisms of key factors such as horizontal spacing, soil layer parameters, and building height on building deformation. The research reveals that the horizontal spacing between the tunnel and the building significantly affects the settlement distribution characteristics. When the spacing is 15 m, the settlement difference between the head and tail of the building reaches 1.94 mm, and the established displacement prediction formula effectively characterizes the nonlinear relationship between horizontal distance and displacement. The elastic modulus of the soil plays a decisive role in deformation, with the maximum settlement in silty clay formation (E is 20 MPa) increasing by 572% compared to sandy mudstone formation (E is 60 MPa), reaching 15.9 mm. Increasing building height exacerbates settlement differences, with the settlement difference of a 30 m high-rise building (2.29 mm) increasing by 487% compared to a 12 m low-rise building (0.39 mm). The study proposes 35 m as the horizontal safety spacing threshold and recommends the Cross Diaphragm (CRD) method or the large pipe roof method for highly compressible formations to control the formation loss rate (<0.5%). The research findings provide a theoretical basis for risk assessment and construction method optimization in tunnel proximity construction in urban core areas.