Research on the safety impact of large diameter shield tunnels underpassing shallow foundation buildings
The metro shield inevitably passes through urban buildings,and the construction disturbance has a significant impact on existing structures,especially on shallow foundation brick and concrete building structures,changes the internal stress distribution of the building to a certain extent,and affects structural safety,requiring special attention.This article takes the crossing of shallow foundation brick and concrete houses by Shenzhen metro as the research background,and uses numerical simulation and on-site measurement comparison analysis methods to explore the settlement principle of soil and the phenomenon of stress redistribution caused by large diameter shield construction.Research has found that when the left and right lines cross,the monitoring points of the houses change in a stepped manner;when excavating on the left side,the houses on the left side near the centerline of the tunnel would experience the largest settlement;when excavating on the right side,the maximum settlement is concentrated in the houses on the right side.Uneven settlement of the building foundation leads to stress concentration on the partition walls and exterior walls near the centerline of the tunnel.Affected by the left line shield tunneling,the center of the building's load-bearing capacity is offset towards the tunnel side,while stress concentration occurs near the outer wall of the double line overlay area during the right line tunneling.Based on the two control indicators of settlement and stress,a method for evaluating the building safety factor is proposed.It is found that the excavation on the right side has a significant impact on the building safety factor,which will reduce the building safety factor.Therefore,it is necessary to strengthen monitoring and carry out timely reinforcement.
large diameter shieldpass through buildingsnumerical simulationsettlement deformationbuilding safety factor
NETL
NSTL
万方数据
