土质边坡加固机理与安全分析方法研究

发布时间：2018-04-18 13:29

本文选题：土坡 + 加固　；参考：《清华大学》2013年博士论文

【摘要】：发展有效的加固土坡安全评价方法，对于治理和防止滑坡灾害、提高土坡加固工程的合理性和经济性、保证其安全性，具有重要意义。本文针对以抗滑桩加固土坡为代表的加固土坡开展研究，自主研发试验设备，主要采用离心模型试验揭示加固土坡的破坏机理和加固机理，在此基础上发展可用于实际工程的抗滑桩加固土坡安全简化分析方法。主要取得如下新成果： 1.自主研发了离心模型试验超重力场中高精度模拟完整桩施工过程的入桩及加载模拟系统、只发生剪切破坏且强度可控的剪切结构桩模型。 2.进行了系列化的抗滑桩等结构加固土坡离心模型试验，揭示了地震、坡顶加载和自重加载等条件下加固土坡的响应特性及主要因素的影响规律。 3．基于离心模型试验揭示了抗滑桩加固土坡的破坏机理，包括：（1）根据土坡滑裂面与抗滑桩的相对位置关系划分为过桩破坏、绕桩破坏、局部破坏和复合破坏等四类破坏模式；（2）观测证实并根据“可测的变形”定量确定了抗滑桩加固土坡存在的渐进破坏过程；（3）揭示了土坡变形局部化过程、滑裂面形成过程和抗滑桩变形过程的耦变机理，这三个过程互为因果、交替发展、耦合变化；（4）抗滑桩加固土坡破坏模式的多样化和破坏特性的复杂性与不同加载条件下土坡的变形特性密切相关。 4．对比分析加固土坡和素土坡离心模型试验结果，发现抗滑桩显著减小土坡变形，其影响在向坡内部传递过程中逐渐减小。揭示了土坡的抗滑桩加固机理：抗滑桩与附近土体发生相互作用并表现为增压效应占优，该效应在抗滑桩显著影响区域内向远桩的坡内部传递，在传递过程中存在着增压效应与抗剪效应的转化，并在潜在滑裂面附近主要表现为抗剪效应，从而延缓了土坡变形局部化的发展过程和滑裂面的形成，增强了土坡稳定性。 5．基于地震离心模型试验揭示了抗滑桩、土工织物、土钉等结构的抗震加固机理，证实了土坡加固机理及其分析理论方法具有良好的普适性。 6．提出了“等效桩土条”模型，通过几何等效和强度等效在定量上将抗滑桩的三维加固效应简化为二维问题，扩展简化毕肖普法建立了抗滑桩加固应变软化土坡稳定性的分析方法并采用离心模型试验结果验证了有效性。将该方法用于实际土坡抗滑桩加固工程的设计分析，确定了加固显著区域。
[Abstract]:It is of great significance to develop an effective method for evaluating the safety of reinforced soil slopes, which is of great significance for controlling and preventing landslide disasters, improving the rationality and economy of soil slope strengthening projects, and ensuring their safety.In this paper, the research on reinforced soil slope reinforced by anti-slide pile is carried out, and the experimental equipment is developed independently. The centrifugal model test is mainly used to reveal the failure mechanism and reinforcement mechanism of the reinforced soil slope.On this basis, a simplified safety analysis method of anti-slide pile for reinforcement of soil slope is developed, which can be used in practical engineering.The main achievements are as follows:1.A pile entry and loading simulation system for simulating the construction process of whole pile with high precision in the super gravity field of centrifugal model test is developed independently. The shear failure and strength controllable shear structure pile model is only occurred.2.A series of centrifuge model tests of reinforced soil slopes with anti-slide piles and other structures are carried out. The response characteristics of the reinforced soil slopes under the conditions of earthquake, top loading and gravity loading are revealed and the influence laws of the main factors are revealed.3.Based on centrifuge model test, the failure mechanism of soil slope strengthened by anti-slide pile is revealed, including: 1) according to the relative position relation between sliding surface and anti-slide pile on the slope, it can be divided into overpile failure and circumferential pile failure.Four kinds of failure modes, namely local failure and composite failure, were observed to confirm and quantitatively determine the progressive failure process of soil slope strengthened by anti-slide pile according to "measurable deformation".) the localization process of soil slope deformation was revealed.The coupling mechanism between the forming process of sliding crack surface and the deformation process of anti-slide pile. These three processes are causality and alternate development.The variety of failure modes and the complexity of failure characteristics of soil slope strengthened by anti-slide pile are closely related to the deformation characteristics of soil slope under different loading conditions.4.By comparing and analyzing the centrifuge model test results of the reinforced soil slope and the plain soil slope, it is found that the anti-slide pile significantly reduces the deformation of the soil slope, and its influence decreases gradually in the process of transferring to the slope.The reinforcement mechanism of anti-slide pile on soil slope is revealed: the interaction between anti-slide pile and nearby soil mass is dominant and the effect is dominant in the area of anti-slide pile, which affects the transfer of the pile to the far pile in the slope.During the transfer process, there is a transformation between the pressure effect and the shear effect, and the shear effect is mainly shown near the potential slip surface, which delays the development of deformation localization and the formation of the sliding crack surface, and enhances the stability of the soil slope.5.Based on the seismic centrifuge model test, the seismic reinforcement mechanism of anti-slide pile, geotextile, soil nailing and other structures is revealed. It is proved that the reinforcement mechanism of soil slope and its analytical theory method have good universality.6.The "equivalent pile-soil strip" model is proposed. The three-dimensional reinforcement effect of anti-slide pile is simplified to a two-dimensional problem by means of geometric equivalence and strength equivalence.The extended simplified Bishop method is used to analyze the stability of strain-softening soil slope strengthened by anti-slide pile and the results of centrifuge model test are used to verify the effectiveness of the method.The method is applied to the design and analysis of the actual soil slope anti-slide pile reinforcement project, and the significant area of reinforcement is determined.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU470

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