【作者】 于洋；

【导师】 尚岳全；

【作者基本信息】 浙江大学 ， 防灾减灾工程及防护工程， 2013， 博士

【摘要】 随着经济建设发展和全球气候变化,威胁人们生命财产安全的大型滑坡越来越多。在滑坡治理工程中,能提供较大抗滑力的双排抗滑桩得到了广泛的应用。但双排抗滑桩受力机理及其影响因素的研究一直落后于应用,很多实际工程只能借鉴单排抗滑桩的设计经验。本文以实际工程监测数据为基础,利用理论分析和数值模拟方法,建立能够考虑双排抗滑桩间“遮蔽效应”的计算模型；研究双排抗滑桩不同锚固深度组合对双排抗滑桩变形、内力、桩侧土压力和双排抗滑桩抗滑力的影响；探讨施工时间差对双排抗滑桩内力的影响；研究简便易行的抗滑桩裂缝判别方法,并对竖向预应力在抗滑桩中的应用进行系统的研究与验证,主要研究内容如下：(1)在假设滑体位移沿深度均匀分布的前提下,引入前排桩与后排桩桩周土体位移比,结合弹性地基梁理论,建立基于土体位移的有连梁双排抗滑桩理论计算模型.基于理论模型的解析解,利用Matlab编程,对双排抗滑桩的内力进行计算,并通过FLAC3D有限差分模型进行验证。(2)基于FLAC3D有限差分模型,探讨不同锚固深度组合对无连粱和有连梁双排刚性抗滑桩变形、内力、抗滑力和桩侧土压力的影响。(3)基于弹性地基梁理论,建立考虑施工时间差的双排抗滑桩计算模型,结合红岩滑坡的工程实测数据,研究施工时间差对双排抗滑桩内力的影响。(4)依据以桩顶位移为参量的抗滑桩计算模型,结合混凝土理论,提出一种基于桩顶位移的裂缝判别方法,用于判断抗滑桩中混凝土出现裂缝的时间及位置,并通过实测数据对判别模型进行验证。(5)基于前人对竖向预应力抗滑桩的研究,提出依据桩顶位移施加预应力的具体方法,实现对抗滑桩裂缝防治的动态控制,同时验证竖向预应力在实际工程中的可行性。通过上述研究,得到以下几点创新性结论：(1)基于土体位移的双排抗滑桩计算模型,通过前排抗滑桩与后排抗滑桩桩周土体位移比来考虑“遮蔽效应”是可行的。相比基于土压力的计算模型,基于位移的计算模型更容易得到解析解；(2)锚固深度对内力、变形、抗滑力和桩侧土压力有明显影响,且此影响与所施加的边界位移大小有关；(3)施工时间差对双排抗滑桩内力与变形有明显的影响,尤其是对先施工的后排抗滑桩。根据前后排抗滑桩最大拉应力比值接近,且最大弯矩之和最小,能够实现施工时间差的优化；(4)利用基于桩顶位移的裂缝判别式,对红岩滑坡抗滑桩裂缝出现的时间及位置进行了判断,通过钢筋应力数据对判断结果进行验证,证明了本文提出的裂缝判别式的可行性和准确性；(5)确定了根据桩顶位移对抗滑桩施加竖向预应力能够实现对抗滑桩裂缝的动态控制。更多还原

【Abstract】 The occurrence of large landslides that threaten the life and poverty of people are becoming more and more frequent as the economic development and climate changing. As a result, the double-row stabilizing piles which can provide larger sliding resistance are widely used in the landslide-control projects. However the study of mechanism of double-row stabilizing pile is in appears of the application of the double-row stabilizing pile, many application cases of double-row stabilizing piles are based on the design experience of single-row stabilizing piles. In this thesis, based on the data of Hongyan landslide project and utilizing the theoretical and numerical methods, a theoretical model in which the "shadow effect" is considered is established. Influences of different scenarios of embedded length of the double-row stabilizing piles on the internal force, the deflection, the sliding resistance and the soil pressure around the piles are studied. Constructional time delay is also introduced in computational model of double-row stabilizing piles. A theoretical method used to predict crack initiation in stabilizing piles is established based on the head displacement data of stabilizing piles. Application of vertical pre-stressing force in the stabilizing piles is systematically studied and validated. The main research contents are:(1). Combined with elastic foundation beam theory, a computational model of double-row stabilizing pile is established by assuming that the displacement of sliding mass is uniformly distributed with depth. In the model, a concept of soil displacement ratio, which is defined as the soil displacement ratio around the rear stabilizing pile to the front stabilizing pile, is introduced. The computational process of the theoretical model is realized by MATLAB. Feasibility of the model is validated by comparing the results between the model and FLAC3D model.(2). Influences of different scenarios of embedded length on the deflection, internal force, sliding resistance and soil pressure are studied using three-dimensional numerical method.(3). Based on the elastic foundation beam theory, a computational model in which the constructional time delay is considered is established. Influences of constructional time delay on the internal force and deflection of double-row stabilizing piles are discussed based on the data of Hongyan landslide project.(4). Based on concrete theory and head displacement of stabilizing piles, a theoretical method used to predict crack initiation in stabilizing is established. The time and position of crack initiation can be determined by this method. The method is validated by data of Hongyan landslide.(5). Based on the researches on vertical pre-stressing force done by the former researchers, specific applied process of pre-stressing force according to head displacement of stabilizing piles is proposed, during which dynamic control of crack can be realized. The feasibility of vertical pre-stress force applied in practical engineering is verified.Some innovative conclusions are drawn through above mentioned researches:(1).The "shadow effect" can be properly considered in the computational method based on displacement of sliding mass. Analytical solution of the method based on the displacement of sliding mass is more convenient to be obtained than that of the method based on soil pressure.(2). Embedded length obviously affects the deflection, internal force, sliding resistance and soil pressure around the stabilizing piles. This kind of influence is dependent on the magnitude of the boundary displacement applied on sliding mass.(3). Construction time delay obviously affects the deflection and internal force of the double-row stabilizing piles, especially for the rear stabilizing pile which is installed earlier. The constructional time delay is optimized based on the principle that the maximum tensile stress in the front and rear stabilizing piles are approximate to each other and the sum of maximum bending moments are the smallest. (4). The time and position of the crack initiation of the stabilizing piles in Honayan landslide are determined by the crack discriminant proposed in this thesis. The results are validated by the stress data of the reinforcement bar, and the feasibility and accuracy are also verified at the same time.(5). Dynamic control of cracks can be realized by applying pre-stressing force according to the head displacement of stabilizing pile.更多还原