砂层盾构隧道端部土体滑移破坏模式分析
发布时间：2018-10-24 12:04
【摘要】：为了分析盾构进出洞时隧道端部土体的失稳破坏模式,为端部土体合理加固范围的确定提供理论依据,基于颗粒流分析程序(PFC),对砂层盾构隧道端部土体的失稳破坏过程和机理进行了数值分析,并采用FLAC3D程序进行对比验证。根据土体滑动规律,给出一种对数螺旋线与直线组合的滑动破坏模式,运用颗粒流计算数据对滑动面进行曲线拟合,并进行相关性分析和显著性检验,得到颗粒摩擦因数取不同数值时的土体滑移面曲线方程。研究结果表明:隧道端部连续墙破除后,土体先在洞门附近发生局部破坏,随后土体颗粒松动破坏向内部发展,颗粒逐步发生位移重定向,最终在土体内部形成了一条显著的滑动破坏面,若隧道埋深较浅,滑动面将延伸贯通至地表;随着土体强度的增高,土体滑移直线倾角变大,对数螺旋线初始半径变小,土体破坏范围相应变小,端部土体越稳定,反之,端部土体滑移范围就会变大,稳定性变差;端部土体经过局部加固后,土体变形较小,内部不能形成滑动面,端部土体稳定性得以提高。
[Abstract]:In order to analyze the failure mode of the end soil of the tunnel when shield machine enters and leave the tunnel, it provides a theoretical basis for the determination of the reasonable reinforcement range of the end soil. Based on the particle flow analysis program (PFC), the failure process and mechanism of soil in the end of shield tunnel in sand layer are analyzed numerically, and the results are compared and verified by FLAC3D program. According to the sliding law of soil mass, a sliding failure mode combining logarithmic helix and straight line is presented. The sliding surface is fitted by the calculated data of particle flow, and the correlation analysis and significance test are carried out. The slip surface curve equation of soil is obtained when the particle friction coefficient is different. The results show that after the end of the tunnel continuous wall is broken, the soil first occurs local failure near the portal, and then the loose failure of the soil develops to the interior, and the displacement reorientation of the particles occurs step by step. Finally, a significant slip failure surface is formed in the soil. If the tunnel is shallow, the sliding surface will extend to the surface. With the increase of soil strength, the slope of slip line becomes larger, and the initial radius of logarithmic spiral becomes smaller. The failure range of the soil becomes smaller and the end soil is more stable. On the contrary, the slip range of the end soil will become larger and the stability will become worse. After the end soil is partially strengthened, the deformation of the soil is smaller and the sliding surface cannot be formed inside. The stability of the end soil can be improved.
【作者单位】： 鲁东大学土木工程学院;北京交通大学土木与建筑工程学院;中国中铁隧道股份有限公司;
【基金】：国家自然科学基金项目(51478213,51278237)
【分类号】：U455.43
，
本文编号：2291357
[Abstract]:In order to analyze the failure mode of the end soil of the tunnel when shield machine enters and leave the tunnel, it provides a theoretical basis for the determination of the reasonable reinforcement range of the end soil. Based on the particle flow analysis program (PFC), the failure process and mechanism of soil in the end of shield tunnel in sand layer are analyzed numerically, and the results are compared and verified by FLAC3D program. According to the sliding law of soil mass, a sliding failure mode combining logarithmic helix and straight line is presented. The sliding surface is fitted by the calculated data of particle flow, and the correlation analysis and significance test are carried out. The slip surface curve equation of soil is obtained when the particle friction coefficient is different. The results show that after the end of the tunnel continuous wall is broken, the soil first occurs local failure near the portal, and then the loose failure of the soil develops to the interior, and the displacement reorientation of the particles occurs step by step. Finally, a significant slip failure surface is formed in the soil. If the tunnel is shallow, the sliding surface will extend to the surface. With the increase of soil strength, the slope of slip line becomes larger, and the initial radius of logarithmic spiral becomes smaller. The failure range of the soil becomes smaller and the end soil is more stable. On the contrary, the slip range of the end soil will become larger and the stability will become worse. After the end soil is partially strengthened, the deformation of the soil is smaller and the sliding surface cannot be formed inside. The stability of the end soil can be improved.
【作者单位】： 鲁东大学土木工程学院;北京交通大学土木与建筑工程学院;中国中铁隧道股份有限公司;
【基金】：国家自然科学基金项目(51478213,51278237)
【分类号】：U455.43
，
本文编号：2291357
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