不同土质中隧道埋深对地表沉降的影响

Response of Ground Surface Settlement due to Tunnel Depth in Different Soil

分析地铁隧道开挖引起的地表沉降对建筑物安全具有重要意义.通过有限差分软件FLAC3D分别对粉质黏土、粉砂、黏土条件下的隧道开挖进行了数值模拟,分析三种不同土质中地表沉降随埋深的变化规律以及三种土质中同一埋深下地表沉降槽曲线的变化规律.结果表明:相同埋深下粉质黏土、粉砂、黏土中的地表沉降值依次减少;粉质黏土、粉砂、黏土的地表沉降槽曲线宽度随埋深的增加而增大;粉砂沉降槽相对于黏土较窄而深,说明土质条件越好,沉降槽宽度越小.

Analysis of ground surface subsidence induced by tunnel excavation is of important significance for security of construction. The excavation process in silty clay,silt and clay was simulated with finite difference software fast Lagrangian analysis of continua in 3D（ FLAC3D）. The law of ground subsidence varies with depth and subsidence trough curves with same buried depth in the three different soils were analyzed. Comparative statistical results and calculation results are as follows： the ground subsidence decreases successively with same buried depth in silty clay,silt and clay. The width of the subsidence trough curves increases with the increase of tunnel depth. The subsidence trough curves of silty clay is more narrow and deeper,which suggests that the better the soil is,the more narrow the subsidence trough curves.