宁波轨道交通水文地质参数试验及工程应用

Engineering Applications and Test of Hydrogeological Parameters in Ningbo Rail Transit

根据宁波市区地下水含水层介质、水动力特征及其赋存条件,划分了宁波轨道交通沿线地层的含水层.采用单孔抽水试验、多孔抽水试验和注水试验,对承压水含水层的水文地质参数进行试验,获得各地层的渗透系数.以某车站基坑工程为例,利用水文地质参数,采用考虑土体强度和不考虑土体强度方法,判定基坑突涌稳定性.结果表明:不考虑土体强度的抗力分项系数取值偏保守,采用考虑土体强度以后,抗力分项系数增幅显著增大.据此提出基坑开挖到22.5m时开始启动降水,并尽可能减少降水时间,以减小对周边环境的影响.

The aquifer layers along the rail are devided according to the groundwater aquifers,hydrodynamic characteristics and occurrence conditions in ground water of Ningbo city.Using the single-well pumping test,water injection test in porous pumping experiments and,the experiment of hydro-geological parameter in confined water are carried out,and the permeability coefficient for all layers is obtained.Then,a station pit is taken for sampling,and by considering soil body strength and not doing so,the bursting Chung stability of found pit is calculated.The results indicate that using the method of not considering soil body strength makes the anti-force points coefficient more conservative,and the coefficient increases largely in case of considering soil body strength.Furthermore,we suggest that when the foundation pit is excavated to 22.5 m,precipitation should begin,and precipitation time should be reduced as short as possible to reduce environmental cost.