淤泥质地层基坑开挖卸荷对下卧区间隧道变形扰动分析  

Analysis of Deformation and Disturbance of Underlying Tunnel Caused by Excavation and Unloading of Foundation Pit in Muddy Strata

作　　者：杨潇 YANG Xiao(POWERCHINA Chongqing Survey,Design and Research Institute Co.,Ltd.,Chongqing 401329,China)

机构地区：[1]中电建重庆勘测设计研究院有限公司,重庆401329

出　　处：《黑龙江交通科技》2024年第10期120-124,共5页Communications Science and Technology Heilongjiang

摘　　要：为获得淤泥质地层中深基坑施工对下卧区间隧道变形扰动的影响,以永嘉广场深基坑斜交上跨区间隧道工程为例,采用实测数据与三维数值分析相结合的方法,分析了基坑开挖对下卧隧道的变形影响,验证了数值模型的合理性。结果表明:淤泥质地层中基坑底距离下卧隧道约两倍隧道洞径时,对隧道上部地层采用搅拌对加固措施可有效控制隧道隆起变形,隧道最大隆起变形8.8 mm,满足变形保护要求;隧道与基坑平面交叠长度越大,隆起变形越大,隆起变形从交叠中心点向基坑两侧平缓过渡减小;隧道与基坑交叠长度较大时,交叠中心范围存在隆起平缓区域,采用一次卸荷大面积开挖方式不利于控制隧道结构隆起变形;同一隧道截面上最大隆起变形处位于拱肩范处、最大水平变形位于拱腰处,隧道形状呈现为“竖椭圆状”的收敛变形。In order to obtain the influence of mid-deep foundation pit construction on the deformation disturbance of the tunnel in the lower lying section,taking Yongjia Square deep foundation pit diagonal tunnel project as the example,the influence of foundation pit excavation on the deformation of the tunnel was analyzed by combining the measured data with the three-dimensional numerical analysis method,and the rationality of the numerical model was verified.The results show that when the distance of the foundation pit bottom in the silt layer is about two times the tunnel diameter,the tunnel uplift deformation can be effectively controlled by using stirring reinforcement measures on the upper layer of the tunnel.The maximum uplift deformation of the tunnel meets the requirements of deformation protection.The larger the overlap length of tunnel and foundation pit,the larger the uplift deformation,and the uplift deformation gradually decreases from the overlap center point to both sides of foundation pit.When the overlap length of tunnel and foundation pit is large,there is a gentle uplift area in the overlap center,and the large-area excavation method of one-time unloading is not conducive to controlling the uplift deformation of tunnel structure.On the same tunnel section,the largest uplift deformation is located at the spinner and the largest horizontal deformation is located at the arch waist,and the tunnel shape is convergent deformation of"vertical ellipse".

关 键 词：淤泥质地层 基坑 区间隧道 实测数据 数值分析 

分 类 号：U231[交通运输工程—道路与铁道工程]