顺层岩体边坡失稳机理与抗滑桩控制体系优化方法

The slope protection is the focus of current national infrastructure constructions such as traffic, water conservancy and hydropower, and the sliding and disaster controls of bedding rock slope are the important theoretical and technical problems of slope protection projects. With the support of many slope protection projects in mid-west China, the instability mechanical model of bedding rock slope and optimization control method of anti-slide pile were systematically studied in this project by means of theoretical research, numerical simulation, physical simulation and on-site test. The instability mechanics model was established based on the statistical analysis of typical sliding cases of bedding rock slope and the identification of occurrence characteristics and instability mode of bedding slope rock mass structure to study the change rules of critical load and displacement of bedding slope rock mass structure giving the corresponding instability criterion. The distributing and response characteristics of anti-slide pile of bedding rock slope were studied considering the interaction between pile and rock mass to reveal the resistance mechanism; the long-term anchorage performance of anti-slide pile of bedding rock slope was studied based on the optimization of pile design parameters and the rheological properties on the structural plane of rock mass around pile in the anchored segment. The effects of pile layout area, pile spacing and relative pile location in space on slope protection were analyzed to achieve the optimization of anti-slide pile control system of bedding rock slope. The research results have important scientific significance and engineering practical value for the sliding and disaster prevention of rock slope.

边坡防护是当前交通、水利水电等国家基础设施工程建设的重点，尤其是顺层岩体边坡滑塌灾害控制是边坡防护工程中的重大理论与技术难题。本项目以我国中西部多项边坡防护工程为依托，综合采用理论分析、数值模拟、物理模拟和现场试验等手段，系统研究顺层边坡滑移失稳机理及抗滑桩优化控制方法。基于典型顺层岩体边坡滑塌案例的统计分析，辨识顺层边坡岩体结构赋存特征及失稳模式，建立顺层岩体边坡失稳力学模型，研究顺层岩体边坡结构的临界荷载及位移变化规律，并给出其相应失稳判据；考虑桩与岩体的相互作用，研究顺层岩体抗滑桩荷载分布规律及桩身响应特性，揭示阻滑机理，优化桩体设计参数，并结合锚固段桩周岩体结构面的流变特性，研究顺层岩体边坡抗滑桩长期锚固性能；分析抗滑桩布设区域、桩间距以及空间相对桩位对边坡防护效果的影响，实现顺层岩体边坡抗滑桩控制体系的优化。研究成果对于岩体边坡滑塌灾害防治具有重要科学意义与工程实用价值。

本项目立足于国家中西部基础设施工程建设急需的边坡防护理论与技术难题，重视顺层岩体边坡的结构赋存特征及抗滑桩的受力特性，通过理论分析、数值模拟、室内试验及现场试验相结合的综合研究方法，深入研究荷载条件下顺层岩体边坡失稳机理及抗滑桩控制优化方法，历经三年完成研究任务如下：.研究了顺层边坡岩体物理场分布规律、失稳机制及破坏模式，基于层状岩体岩层倾角、岩层厚度、滑体尺寸以及结构面强度等结构特征，分别基于小变形理论及非线性大变形理论建立滑体失稳力学模型，得到了顺层岩体边坡结构的临界荷载尺寸效应规律及位移变化规律，并给出其相应失稳判据。.基于顺层岩体的失稳荷载判据，研究了顺层岩体抗滑桩荷载分布规律及桩身响应特性，基于顺层岩体边坡的失稳力学模型和加桩后层状岩体应力重分布情况，结合桩-岩模量比、桩体与岩层夹角、岩体强度及桩体抗剪特性等影响因素，分析了抗滑桩受荷段与锚固段的力场分布规律，给出了顺层边坡抗滑桩的合理锚固深度；并结合试验研究了层状岩体结构面强度-变形随时间的变化规律，分析了顺层边坡抗滑桩防护体系的长期阻滑效应。.针对顺层岩体边坡的失稳模式与空间应力场分布特征，基于抗滑桩加固的受力特性，对比不同工况下防护前后的应力场跃迁表征规律，优选抗滑桩布设区域；通过对横排桩间岩拱效应的研究，建立抗滑桩横排桩间距、桩径及边坡岩体拱圈厚度之间的关系，得到顺层边坡抗滑桩防护体系的最合理横排桩间距；考虑纵排桩的边坡滑动荷载分担情况，研究抗滑桩群纵向排桩数目与纵向桩位对桩身力学性能和边坡整体结构锚固效应的影响，通过对比抗滑桩群在布设区域内不同空间相对位置的边坡整体位移控制情况，确定顺层边坡抗滑桩群防护的合理空间桩位。.本项目获发明专利6项，发表文章12篇，其中SCI/EI收录8篇，培养硕士研究生2名。项目成果应用于湖北秭兴高速公路、兰新铁路等多处边坡灾害控制工程中，取得了一定的经济社会效益。