盾构隧道深层土体沉降槽宽度系数计算方法研究

Study on Calculation Method of Width Coefficient of Subsurface Settlement Trough in Shield Tunnel

收集了12组盾构法隧道施工引起的深层土体沉降实测数据,研究深层土体沉降槽宽度系数i(z)随着地层深度z增加产生的变化规律。研究结果表明:i(z)随着z的增加而逐渐减小;i(z)/i(z=0)与(1-z/h)(h为隧道轴线埋深)之比在黏性土中基本呈幂函数关系,砂土中基本呈线性关系。对姜忻良计算公式进行了修正,使其具有更广泛的适用性。通过回归分析,提出一个新的i(z)经验计算公式。通过反分析以及与解析解进行比较,给出这两个公式计算参数的取值范围。算例分析表明,这两个公式均能较好的拟合实测值,可考虑不同土质条件,包括黏性土和砂类土,适用范围较广。

12 cases of measured data of subsurface settlement induced by shield tunnel construction were collected.The change regularity about width coefficient i（z） of subsurface settlement trough with soil depth z was studied.It shows that（1） i（z） is smaller with the increased z;（2） power function relationship is existed in the ratio between i（z）/i（z=0） and（1-z/h）（h is tunnel axis depth） in clayey soil,while the value of i（z）/i（z=0） is linear with（1-z/h） in sandy soil.Broader adaptability was obtained by modifying the formula of Jiang X L.A new empirical equation of i（z） was advanced by regressive analysis.Both value ranges of empirical equation parameters were advanced by back analysis and comparison between the presented method and analytical solution.The analytical calculation shows that both formulas mentioned above not only are suitable for fitting measured data but also can be used for different soil conditions such as clayey soil and sandy soil.