土体参数对盾构隧道衬砌与土体共同作用影响分析

Influence of Soil Parameters on Response of Shield Tunnel Lining Considering Soil-Structure Interaction

为了解决在盾构隧道结构分析中土与结构共同作用如何有效考虑的问题,借鉴连续介质模型的组成体系与加载方式,基于数值分析的方法建立土与隧道共同作用的计算模型,其中管片接头的转动刚度非线性与衬砌三维拼装效应均被考虑,计算结果与模型试验结果吻合良好。针对侧压力系数和土体刚度展开参数分析,研究结果表明:1)随着侧压力系数和土体刚度的减小,衬砌椭圆化变形增加,同时衬砌拱顶弯矩增加,纵向接头的相对转动主导了衬砌的椭圆化变形;2)随着侧压力系数的增加,土体高应力分布区由拱顶月牙形朝环周均匀分布转变,拱腰侧低应力区逐渐消失,同时隧道椭圆化变形趋于0;3)土体刚度对土体应力分布改变影响较小,但随着土层刚度的增加,衬砌环周应力条件被明显改善,拱顶的椭圆化荷载同样有朝环周均布荷载转变的趋势。

The combined action of soil and structure should be effectively considered when it is applied to the structural analysis of shield tunnel lining.Based on the composition system and loading method of the continuum model,a numerical simulation model considering the interaction between soil and tunnel,rotation stiffness nonlinearity of segment joint,and 3 D assembly effect of lining is established,and the calculation results coincide with the test results well.and the numerical results matched well with the test results.A parametric analysis is conducted on the lateral pressure coefficient and soil stiffness.The results show the following.(1)With the decrease of lateral pressure coefficient and soil stiffness,the ovalisation deformation of lining and the bending moment of the lining crown increase.The ovalisation deformation of the lining is dominated by the relative rotation of longitudinal joints.(2)The high stress area of the soil changes from the crescent shape at the crown to the uniform distribution around the circumference as the lateral pressure coefficient increases,and the low stress area at haunch gradually disappears,while the ovalisation deformation of the tunnel tends to be 0.(3)The soil stiffness has less effect on the stress distribution of the surrounding soil,whereas the circumferential stress conditions is significantly improved with the increase of the soil stiffness,and the ovalisation load on the crown also has a trend towards circumferentially uniform.