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建筑岩质边坡稳定与控制研究
Research on the Stability of Building Rock Slope and Its Control
【作者】 吴曙光;
【作者基本信息】 重庆大学 , 岩土工程, 2005, 博士
【摘要】 岩质边坡是一类重要的岩土工程,在山地城市建设、公路、铁道、水利、矿山和国防等建设工程中十分常见。随着城市建设及土地开发,建筑物周边的环境边坡——建筑岩质边坡在山地城市建设中日益增多。建筑岩质边坡虽然规模不大,但由于其与周边环境、人类活动联系密切,会直接影响到建筑主体工程的可行性论证、经济指标和正常使用等。目前对于一些建筑岩质边坡的破坏机制认识尚不足,一方面过于保守的设计造成边坡工程造价过高、极不经济;另一方面边坡经常发生失稳事故,危及人民的生命财产,给国家带来了巨大的损失。因此,有必要加强研究建筑岩质边坡的稳定性及其控制。本文以结构较完整的无外倾结构面建筑岩质边坡为研究对象,重点针对建筑岩质边坡的稳定性分析及其控制问题进行了深入的研究,得到了一些有意义的研究成果,并在实际工程中加以了应用,取得了显著的经济效益和社会效益。论文的主要工作有: 1)建立了建筑岩质边坡岩体卸荷力学参数的确定方法,结合现场调研和理论分析,在确认边坡整体稳定的前提下,采用岩体卸荷非线性力学方法(变刚度法)研究了边坡的渐进破坏过程并确定了坡顶应力卸荷区范围,提出了无外倾结构面建筑岩质边坡岩石侧压力分布规律及相应的计算公式。2)通过分析传统的边坡支挡结构设计不利于最终有效控制边坡稳定性的原因,提出了建筑岩质边坡稳定性“全过程动态控制”的新概念,阐述了建筑岩质边坡稳定性全过程动态控制的基本理论和三维控制体系的构成。3)结合建筑岩质边坡的研究实践,系统地研究了建筑岩质边坡的稳定性控制,建立了一套较为完善的建筑岩质边坡稳定性控制的技术方法体系。提出了通过控制坡顶关键块体来确保无外倾结构面建筑岩质边坡整体稳定的新理论,并通过数值分析及边坡监测,验证了该控制方案的可靠性及相对于常规方案的优越性。4)通过对重庆市渝中区旧城改造桂花园小区工程实例成功经验的研究总结,提出了研究边坡顶部建造高层建筑物时坡顶地基及边坡整体稳定性综合分析方法。利用超载法模拟了边坡顶部建造高层建筑物时边坡的变形破坏过程,并提出了坡顶建筑物地基及边坡的安全判据。5)通过分析斜坡上地基的应力分布,以及根据现场载荷试验资料和室内试验对比资料,提出了以天然湿度条件下的单轴受压强度作为岩石质量指标确定坡顶建筑物地基承载力的方法;基于坡顶建筑物基础设计与边坡防治工程设计相结合的原则,通过分析影响坡顶建筑物及边坡的整体稳定性的控制因素,提出了采用
【Abstract】 Rock slope is a common type in practiced projects such as mountain city construction, road, railway, water conservancy, mining engineering and national defense. With development of city construction, more and more problems appear in building rock slope. Although building rock slope is not too large in dimensions, it plays an important role for main body of whole construction in argumentation of feasibility, economic guideline, normal operation, etc. It must be mentioned here that instability of slopes due to lack of cognition about failure mechanism of construction rock slope has resulted in huge loss for nation and people, whereas reasonable design and support of slopes evidently benefit people. Therefore, it is necessary to research deeply the stability of rock slope and its control. Stability of building rock slope with relatively intact texture and its control are studied deeply in the paper. The significant results are obtained, and the results are applied to actual rock engineering, the prominent economic and social benefits are attained. Main points are shown as follows: (1) The method to determine unloading mechanics parameters of the slope rock mass is established. Combining field test and theoretical analysis, the mechanism of occurrence, development and destruction of rock slope’s gradual failure have been studied. Based on unloading nonlinear rock mass mechanics, unloading zone on the top of slope is defined. The distribution law of wall pressure in rock slope and the corresponding calculation formulas are given. (2) A new idea of “information control on complete process”to stability of building rock slope is brought up by analyzing traditional slope timbering design against ultimately efficient slope stability. The basic theory of the new idea and the structure of three dimensional control systems are also expounded. (3) Combining the research practice on building rock slope, stability control on building rock slope is studied. At the same time a series of comparative perfect technology systems of stability and its control of construction rock slope are established. A control scheme of anchoring crucially the key body of slope top for construction rock slope without extroversion is proposed. Reliability and advantage relative to general scheme of this scheme are validated by using numerical analysis and slope monitoring at the stage of construction and completion. (4) Based on successful conclusion of Guihuayuan subzone project, one of reconstruction projects of old city in Yuzhong District, Chongqing, the synthetical analysis method about whole stability of slope and building foundation on the top of slope is provided while researching construction of tall building on the top of slope. The process of deformation and failure are simulated when tall buildings are built on the top of slope. Security judgments about slope and building foundation on the top of slope are determined. (5) Through analysis on stress distribution in the foundation on the top of slope, the ways to determine the subgrade bearing capacity of building on the top of slope are proposed, based on uniaxial compressive strength on the condition of natural moisture. Combining design of building foundation on the top of slope and design of prevention projects for slope, by analyzing on these factors which affect on building on the top of slope and whole stability control of slope, the scheme is brought up ,namely “人”shaped anchor used for controlling the monolithic stability of buildings on the top of slope and the slope. (6) According to field test and theoretical analysis, the difference of mechanisms and distributing behaviors of shear stress between pressure-type and tensile-type anchor are analyzed. Distributing behaviors of shear stress with hyperbolic function in the pressure-type anchor is established. Failure mode of pressure-type anchor in rock is proposed, and design formula and the corresponding parameter of pressure-type anchor are determined in accordance with three failure modes. Moreover, the advantages of pressure-type anchor applied in building rock slope project are sum up.
【Key words】 Building rock slope; Failure mechanism; Numerical analysis; Stability analysis; Stability control; Pressure-type anchor;