城市浅埋隧道地表沉降规律与控制分析

发布时间：2018-03-07 06:08

本文选题：浅埋隧道　切入点：地表沉降　出处：《山东科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：城市地铁建设有效解决了交通拥堵问题,在全球范围内地铁建设已经成为开辟地下空间的主要方式。但是,地铁隧道的开发建设也面临着施工会产生周围岩土层环境改变,邻近建(构)筑物变形以及地表沉降变形。(1)隧道开挖不采取支护条件下,对不同覆跨比浅埋隧道地表沉降规律进行数值模拟分析。分析结果表明地表沉降变形在2.5倍H/D以内逐渐增加,2.5倍H/D以外逐渐减小,确定覆跨比强影响区为隧道埋深2.5D以内,弱影响区为2.5D以外。(2)基于Midas/GTS对青岛地铁浅埋暗挖区段进行了不同支护方式选型与优化,通过分析经济效果和控制效果确定采用加长锚杆、地层注浆、加厚二衬是最经济合理的支护方式。(3)对青岛地铁3号线浅埋暗挖段实测数据进行分析,其地表沉降规律与Peck经验公式基本一致,隧道地表沉降最大值发生在隧道中心点位置,向两侧逐渐减小。对实测横断面数据进行Peck公式反分析,确定该区段地表沉降槽宽度系i为8.47,有效摩擦角为46.54°,地层损失率约为1.15%。通过反分析得出参数确定预测Peck公式,对后续断面进行预测分析,结果表明在相同地层条件和埋深下,预测公式能够较准确预测变形,在不同区段不同埋深下,地表沉降预测效果较差,因此,Peck公式反分析应在相同条件下进行。(4)地表沉降某一点随时间变化规律与Logistic模型变化规律基本一致,通过线性拟合取得Logistic预测曲线,对测点后续时间变化进行预测,结果表明该模型在对最终结果的预测上误差较小,中期误差较大。在前期小样本数据条件下,Logistic模型可以对施工中地表沉降随时间变化的最终沉降进行预测。
[Abstract]:Urban subway construction has effectively solved the problem of traffic congestion, and subway construction has become the main way to open up underground space in the world. However, the development and construction of subway tunnel is also faced with the change of surrounding rock and soil environment. Adjacent building deformation and ground subsidence deformation. 1) the tunnel is excavated without support. The numerical simulation analysis of the surface settlement law of shallow buried tunnels with different overlying span ratio shows that the ground subsidence deformation gradually increases within 2.5 times of H / D and decreases gradually, and the influence area of overlying span ratio is within 2.5 D of buried depth. The weakly affected area is 2.5D.) based on Midas/GTS, different support methods are selected and optimized for the shallow underground excavation section of Qingdao Metro. By analyzing the economic effect and the control effect, it is determined to adopt the lengthened anchor rod and the stratum grouting. Thickening second lining is the most economical and reasonable supporting method. (3) the measured data of shallow underground excavation section of Qingdao Metro Line 3 are analyzed. The law of surface subsidence is basically consistent with Peck's empirical formula, and the maximum value of tunnel surface settlement occurs at the center of tunnel. It is found that the width system of surface subsidence trough I is 8.47, the effective friction angle is 46.54 掳, and the loss rate of formation is about 1.15 by the back analysis of the measured cross-section data. The Peck formula for predicting the parameters is obtained. The prediction results of subsequent sections show that under the same formation conditions and buried depth, the prediction formula can accurately predict deformation, and the prediction effect of surface subsidence is poor under different buried depths in different sections. Therefore, the back-analysis of Peck formula should be carried out under the same conditions. (4) the variation law of surface subsidence with time is basically the same as that of Logistic model. The prediction curve of Logistic is obtained by linear fitting to predict the change of subsequent time of measuring point. The results show that the prediction error of the final result is small and the medium term error is large. Under the condition of small sample data in the early stage, the Logistic model can predict the final settlement of surface subsidence with time in construction.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4;P642.26

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