双排抗滑桩受力影响因素研究

发布时间：2018-08-20 13:21

【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。
[Abstract]:With the development of economic construction and global climate change, there are more and more large landslides threatening people's lives and property. In landslide control engineering, double row anti-slide pile which can provide large anti-slide force has been widely used. However, the research on the mechanics and influencing factors of double-row anti-slide piles has been lagging behind the application, and many practical projects can only draw lessons from the design experience of single-row anti-slide piles. Based on the actual engineering monitoring data, this paper establishes a calculation model which can take into account the "shielding effect" between double-row anti-slide piles by using theoretical analysis and numerical simulation method, and studies the deformation of double-row anti-slide piles with different anchoring depth combinations. The influence of internal force, soil pressure on pile side and anti-slide force of double-row anti-slide pile; discuss the influence of construction time difference on internal force of double-row anti-slide pile; study the simple and easy method to judge the crack of anti-slide pile, The application of vertical prestress in anti-slide pile is systematically studied and verified. The main contents are as follows: (1) under the assumption of uniform distribution of sliding body displacement along the depth, the displacement ratio of soil around the front row pile and the back row pile is introduced. Based on the theory of elastic foundation beam, the theoretical calculation model of double-row anti-slide piles with connected beams is established based on soil displacement. Based on the analytical solution of the theoretical model, the internal force of the double-row anti-slide pile is calculated by Matlab programming, and verified by the FLAC3D finite difference model. (2) based on the FLAC3D finite difference model, The effects of different anchoring depth combinations on deformation, internal force, anti-slide force and soil pressure of pile side are discussed. (3) based on the theory of elastic foundation beam, The calculation model of double-row anti-slide pile considering the construction time difference is established, and the influence of the construction time difference on the internal force of the double-row anti-slide pile is studied in combination with the measured data of Hongyan landslide. (4) based on the calculation model of anti-slide pile with the displacement of the pile top as the parameter, Combined with concrete theory, a crack discrimination method based on pile top displacement is proposed, which can be used to judge the time and position of concrete crack in anti-slide pile. The discriminant model is verified by the measured data. (5) based on the previous research on the vertical prestressed anti-slide pile, the concrete method of applying prestressing force according to the displacement of the pile top is put forward to realize the dynamic control of anti-slide pile crack prevention. At the same time, the feasibility of vertical prestress in practical engineering is verified. Through the above research, some innovative conclusions are obtained as follows: (1) the calculation model of double-row anti-slide pile based on soil displacement is feasible to consider the "shielding effect" through the ratio of soil displacement around the front row anti-slide pile and the back row anti-slide pile. Compared with the calculation model based on earth pressure, the model based on displacement is easier to obtain analytical solution. (2) Anchorage depth has obvious influence on internal force, deformation, anti-slide force and soil pressure on pile side. This effect is related to the magnitude of the boundary displacement applied. (3) the construction time difference has obvious influence on the internal force and deformation of the double-row anti-slide pile, especially on the post-row anti-slide pile. According to the ratio of maximum tensile stress is close and the sum of maximum moment is minimum, the construction time difference can be optimized. (4) the crack discriminant based on pile top displacement is used. The time and position of cracks of anti-slide pile in Hongyan landslide are judged, and the results are verified by the data of steel bar stress, which proves the feasibility and accuracy of the crack discriminant proposed in this paper. (5) the dynamic control of anti-slide pile crack can be realized by applying vertical prestressing force according to the displacement of the pile top.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU473.1

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