【作者】 王伟；

【导师】 刘书贤； 杜平；

【作者基本信息】 辽宁工程技术大学 ， 岩土工程， 2019， 博士

【摘要】 近些年来随着我国地铁建设的快速发展,在城市商业经济区域中形成了大量的地铁隧道结构,使得地铁隧道周边邻近建筑物有着数量多、空间交错影响大、结构及基础形式复杂的特点,地铁隧道施工过程中诱发地表坍塌失稳严重威胁着周边建筑物的安全,极易造成严重的经济损失,因而如何保证地铁隧道施工过程地表的稳定性成为了城市地铁建设不可忽视的问题。地铁施工诱发地表坍塌失稳受到众多因素的影响,且因素复杂,通常认为地铁隧道施工方法的不同诱发地面坍塌失稳机制的区别较大。本文以沈阳地铁工程为依托,基于弹塑性力学、相似理论、Peck沉降理论、回归分析和数值计算软件FLAC3D,采用理论分析、相似模型试验、现场检测与数值计算相结合的方法对地铁隧道施工诱发地表坍塌失稳的机理进行了初步分析,并围绕地铁隧道的不同开挖工法所引起的地表沉降规律进行了如下研究:(1)基于沈阳地铁的工程背景,通过1:50相似比的缩尺模型,进行了地铁隧道相似模型的开挖试验。将试验所得数据与实测工程数据对比分析,并验证了修正后的Peck公式系数的正确性。(2)基于FLAC3D三维数值模型,研究了地铁隧道开挖的CRD法、台阶法、盾构法所引发的地表沉降变形规律。通过分析不同开挖工法的地表沉降及隧道结构的应力分布发现;V级围岩,三种工法引发的地层横截面竖向位移对称分布,CRD法产生的地表最终沉降量最大,其值为0.068m,盾构法产生的地表最终沉降量最小,其值为0.0348m;在隧道开挖过程中,CRD法的隧道最大主应力最先达到稳定,盾构法和上下台阶法的隧道的最大主应力次之。沉降量最大的是CRD法,其值为0.068m,台阶法最终沉降量为0.038m,盾构法沉降量为0.0348m。(3)基于地表沉降的实测值与测点距隧道轴线的距离的对应关系,以Peck公式为基础,利用回归法对实测数据进行线性回归分析。对回归后的lnS(x)及原测数值进行了对比,将回归后沉降曲线与Peck公式预测曲线对比分析,发现回归后的曲线能更好的显示沉降规律,并满足实测点的分布规律。得到适合于沈阳地铁某区段的最大沉降量修正系数α。地表最大沉降修正参数α分布区间主要集中在0.3～0.7,占到了所有数值分布的75%,可以对地表最大沉降值进行良好的修正。根据回归后的沉降曲线,分析β的区间分布,得到了沉降槽修正系数β,β分布区间主要集中在0.4～0.9,占到了所有数值分布的92.75%,可以较好的修正沉降槽。该论文有图126幅,表30个,参考文献125篇。更多还原

【Abstract】 With the rapid development of China’s subway construction in recent years,a large number of subway tunnel structures are formed in the urban commercial economic region,which makes the adjacent buildings around the subway tunnel have a large number of structures,large spatial interlacing effects,and complex structures and basic forms.The collapse of the surface induced by subway tunnel construction threatens the safety of surrounding buildings.It can easily cause serious economic losses.Therefore,it is an non-negligible question that how to ensure the stability of the subway tunnel construction process.Subway construction causes the collapse of the surface is affected by many factors which are prettycomplex.The difference in the mechanism of subway tunnel construction induced the collapse of the ground and it has a great distinction.The article is based on Shengyang Metro Project.We use elastoplastic mechanics,similarity theory,Peck sedimentation theory,regression analysis and numerical calculation software FLAC3D to study the mechanism and prevention of surface collapse.The combination of theoretical analysis,similar model test,on-site detection and numerical calculation is also used in the study of the mechanism of instability of surface collapse.The mechanism analysis of the surface collapse induced by subway tunnel construction was analyzed,and the ground settlement law caused by different excavation methods of subway tunnel was studied.The main research contents of this paper are as follows:(1)The engineering is based on Shenyang Metro.We produced a scale model with a 1:50 similarity ratio.We conducted an excavation test of a similar model of a subway tunnel.The experimental data is compared with the measured engineering data,and the correctness of the modified Peck formula coefficients is verified.(2)The study is based on the FLAC3D three-dimensional numerical model.We study the law of surface settlement and deformation caused by CRD method,step method and shield method in subway tunnel excavation.We analysis of surface settlement and stress distribution of tunnel structures.The vertical displacement of the cross-section of the stratum caused by the three methods is symmetrically distributed.The surface generated by the CRD method is with the largest final settlement and the shield method is the smallest.During the tunnel excavation process,the principal stress of the tunnel of the CRD method is first stabilized.The shield method and the upper and lower steps are second.(3)We study the correspondence between the measured value and the distance of the measuring point from the tunnel axis.Based on the Peck formula,the regression analysis is used to perform linear regression analysis on the measured data.The lnS(x)after regression and the original measured values are compared.We compare the settlement curve after regression with the prediction curve of Peck formula.It is found that the curve after regression can better show the law of sedimentation.And it meets the distribution law of the measured points.The maximum settlement correction coefficient a suitable for a certain area is obtained.The maximum distribution correction parameter a of the surface is mainly concentrated in 0.3～0.7,accounting for 75%of all numerical distributions.It can correct the maximum settlement value of the surface.According to the settlement curve after regression,we also analyze the interval distribution of β.The β distribution interval is mainly concentrated in 0.4～0.9,accounting for 92.75%of all numerical distributions.It can better correct the settlement tank.The paper has 126 pictures,30 tables,and 125 references.更多还原