大断面矩形顶管隧道开挖面土体稳定性研究

发布时间：2018-01-20 12:23

本文关键词： 矩形顶管砂砾石地层开挖面稳定性数值模拟支护力　出处：《现代隧道技术》2017年05期 　论文类型：期刊论文

【摘要】：文章以采用土压平衡矩形顶管法施工的内蒙古科技大学地下通道为背景,采用理论分析、数值模拟、现场监控量测等手段,对砂砾石地层条件下矩形顶管开挖面的主动和被动破坏规律进行了研究,主要得到了以下结论:(1)考虑顶管隧道开挖面为矩形断面的特点,建立梯形楔体计算模型,推导出开挖面主动破坏时的极限支护应力计算公式并应用于实际工程,采用该公式计算得到的极限支护压力与数值模拟计算结果相差较小,两种研究方法得到了相互验证;(2)采用FLAC3D数值模拟得到的地表沉降槽与实测地表沉降槽形态基本相似,近似服从正态分布,且地表沉降值基本接近;(3)随着支护应力比的减小,开挖面塑性区逐渐由开挖面前方向斜上方发展,当支护应力比为0.165时,开挖面前方土体水平位移骤然增加,开挖面塑性区延伸至地表,土体丧失整体稳定性,发生主动破坏,且从开挖面失稳后地表塑性区扩展形态来看,基本接近梯形楔形体形状,从而验证了解析公式计算模型的合理性;(4)随着支护应力比的增大,开挖面前方土体塑性区自开挖面顶部向地表斜上方延伸,当支护应力比为3.0时,塑性区发展至地面,此时土体失稳,发生被动破坏,其塑性区范围远小于主动破坏时的塑性区。
[Abstract]:Based on the underground passage of Inner Mongolia University of Science and Technology which is constructed by using the method of earth pressure balanced rectangular pipe jacking, the paper adopts theoretical analysis, numerical simulation, field monitoring and measurement and so on. In this paper, the active and passive failure rules of the excavated surface of rectangular pipe jacking under the condition of sandy gravel are studied, and the following conclusions are obtained: (1) considering the characteristics of rectangular section of the excavated surface of the jacking tunnel. The calculation model of trapezoidal wedge is established, and the formula of ultimate support stress is deduced and applied to practical engineering. The difference between the limit support pressure calculated by the formula and the numerical simulation results is relatively small. The two research methods are verified by each other. (2) the surface subsidence trough obtained by FLAC3D numerical simulation is basically similar to the measured surface settlement trough, which is similar to normal distribution, and the surface settlement value is close to that of the measured surface settlement trough. 3) with the decrease of the support stress ratio, the plastic zone of the excavation surface gradually develops from the direction of the excavation to the top of the slope. When the support stress ratio is 0.165, the horizontal displacement of the soil in front of the excavating surface increases suddenly. The plastic zone of the excavated surface extends to the surface, the soil loses the whole stability, and the active failure occurs, and the shape of the plastic zone after the instability of the excavated surface is close to the shape of the trapezoid wedge. Thus, the rationality of the analytical formula calculation model is verified. 4) with the increase of the support stress ratio, the plastic zone in front of the excavating surface extends from the top of the excavating surface to the top of the surface. When the support stress ratio is 3.0, the plastic zone develops to the ground and the soil is unstable. The range of plastic zone of passive failure is much smaller than that of active failure.
【作者单位】：内蒙古科技大学土木工程学院;内蒙古科技大学数理与生物工程学院;包头城建集团股份有限公司;
【基金】：内蒙古科自然科学基金项目(2017MS(LH)0523) 内蒙古自治区高等学校科学技术研究项目(NJZY14167)
【分类号】：U455.4
【正文快照】： 3包头城建集团股份有限公司,包头014010)修改稿改回日期:2017-03-221引言近年来,土压平衡矩形顶管技术开始广泛运用于我国行人过街地下通道、地铁车站出入口过街通道、下穿城市道路的隧道、地下共同沟、城市地下商业空间开发等工程中[1],采用该种地下非开挖技术修建的隧道具有

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