强卸荷条件下岩体流变特性对高边坡锚固效果影响研究

Rheological properties of unloading zone rockmass under strong unloading condition are crucial in the analysis of long-term stability of high slope anchoring engineering. Such rheological properties are not considered in current design of high slope anchoring engineering. Therefore, it is urgent to carry out research on influence of rheological properties on high slope anchoring effects under strong unloading condition. Research is conducted by taking the typical high slope anchoring engineering in western mountain erea as example. Engineering geological conditions of this high slope should be first investigated. The triaxial unloading confining pressure test for high slope zone rockmass are done to determine the mechanical properties of the roakmass under high ground stress. the unloading confining pressure rheological tests of the rockmass are done, the unloading rheological charateristics and mechinism of rocks are examined to obtain their unloading rheological constitutive model and long-term strength. The physical model test and in-situ monitoring methods shall be used in theis research.Firstly, the comback analysis is used to determine parameters of the high slope and anchoring structure. Then, the deformation, failure rule and stability of high slope anchoring engineering system under strong unloading condition are summarized regardless of rheology. Based on unloading rheology theory, the nonlinear deformation and failure of this system and its long-term stability are investigated, and the internal force and the long-term strength of the high slope anchoring structure system are studied. Based on the above research, the effect of unloading rheological properties of rockmass on the internal force and the long-term stability of the high slope-anchoring structural system are analyzed. This research aims to evaluate the effect of unloading rheological properties on anchoring engineering, and present correction method of the safety coefficient in anchor design by considering unloading rheological influences. The research achievement could be benefit for high slope anchor design in western mountain area.

强卸荷条件下卸荷带岩体流变特性影响高边坡锚固工程的长期稳定，目前高边坡锚固工程设计未考虑岩体流变特性，急需开展强卸荷条件下卸荷带岩体流变性质对高边坡锚固效果影响的研究。选择西南地区典型高边坡锚固工程，查明工程地质条件。进行强卸荷条件下岩石三轴卸围压试验和卸荷流变试验，研究高应力水平下岩体强卸荷变形特性和流变机理、劣化规律，确定卸荷流变本构模型及长期强度。采用实际材料物理模型试验与现场监测相结合的方法，进行强卸荷条件下高边坡与锚固结构参数智能反演；模拟分析不考虑卸荷流变时高边坡-锚固结构体系变形破坏规律及稳定性；基于卸荷流变理论，模拟分析高边坡-锚固结构体系非线性变形破坏规律及长期稳定性，研究锚固结构内力及长期强度变化规律；分析岩体卸荷流变特性对高边坡-锚固结构体系内力及长期稳定性的影响，评价其对锚固效果影响；提出考虑卸荷流变影响的锚固工程设计安全系数修正方法，为高边坡锚固工程设计提供依据。

随着“一带一路”战略和长江经济带等国家战略实施，越来越多的大型基础设施工程相继在地质条件复杂、滑坡地质灾害频发的地区规划、建设，为保证这些重大工程的顺利实施和正常运行，保护人民生命财产安全，研究强卸荷作用下高边坡卸荷带岩体变形破坏规律，高边坡防治结构的治理效果，治理工程在实际使用期内的长期安全性，具有重大研究意义。.本项目主要进行了如下研究： .1.研究强卸荷条件下卸荷带岩体的力学特性及参数条件，建立强卸荷条件下卸荷带岩体的本构方程和破坏判据。 .2.研究典型高边坡锚固结构自身承载特征，锚索荷载传递机理和受力分析及内力计算方法，建立锚索动态响应模型。研究强卸荷条件下，植入锚固结构后，锚索内力变化与响应规律。 .3.研究强卸荷条件下，高边坡治理前应力场变化特征，揭示其非线性时效变形规律，分析其长期稳定性。 .4.分析岩体流变特性对高边坡-锚固结构体系内力及长期稳性的影响，评价高边坡卸荷带岩体流变特性对锚固效果的影响；提出强卸荷、考虑卸荷带岩体流变特性影响条件下，锚索设计的安全系数修正方法，为强卸荷条件下高边坡锚固工程设计提供依据。.通过研究得到了以下重要结果和数据：.1. 通过系统工程地质调查，查明了武隆县典型高边坡工程地质条件，进行了岩体卸荷带划分，查明了岩体结构特征。.2. 进行了三叠系中统巴东组第三段薄层状泥灰岩和灰岩卸荷流变试验，确定两种岩石的流变参数，建立卸荷流变本构模型。并与常规三轴试验结构进行了对比。.3. 按期进行了野外高边坡、预应力锚索防治结构的应力应变、位移监测。.4. 结合依托工程开展了锚索锚固体剪应力分布特征现场试验，基于试验结果和已有理论分析成果，进一步阐述了不同类型锚索的锚固性能和锚固机理，分析了三类基坑锚索的承载能力及位移延性的大小关系为：压力分散型锚索＞拉力分散型锚索＞拉力集中型锚索。