衡重式桩板挡墙变形性状的研究

发布时间：2018-10-12 14:44

【摘要】：衡重式桩板挡墙是一种新型支挡结构,由桩、锁口梁、柱板墙和衡重台(卸荷板)等构件组成。由于设置了与墙身刚性连接的卸荷板,其减小了卸荷板下部结构作用土压力,并为桩提供一个反弯矩(相对于土压力作用引起的弯矩),使结构的内力分布均衡；同时使支挡结构离开土体的位移趋势得到一定的限制。该类挡墙由于卸荷板的卸荷作用、反弯矩作用及结构-上的相互作用,结构的受力-变形性状较其他类型的桩板式挡墙更为复杂。在前期研究工作中,对结构的受力特性已进行了较深入的研究,但该类挡墙的变形性状尚不明确,变形计算方法和控制变形的设计方法还有待研究。研究衡重式桩板挡墙的变形性状,提出变形控制设计方法,进一步完善设计理论,对于该类结构的进一步推广应用具有重要的理论和工程实际意义。本文基于弹性地基梁法,按“两段法”推导了衡重式桩板挡墙内力、变形解析分析方法。该分析方法计算结果与弹性杆系有限元方法的计算结果进行比较,计算结果比较接近；与模型试验、现场测试结果比对,本文分析方法计算结果与实测结果符合,验证了该分析方法的可靠性和合理性。用本文提出的解析分析方法,研究卸荷板的埋深和板宽对结构变形的影响,分析卸荷板的合理埋深和板宽位置,分析结果得到了模型试验、数值分析方法的验证。此外,还分析了桩长、桩径和土体参数对结构变形的影响。采用FLAC软件,考虑土与结构共同作用的条件下,模拟填方挡墙和挖方挡墙不同施工顺序进行数值分析,与本文分析方法、杆系有限元方法的结果进行了对比。得出结论：在考虑土与结构相互作用的条件下,数值分析计算的变形较小；挖方挡墙按增量法与总量法计算的结构内力和变形比较接近；填方挡墙按增量法和总量法计算的结构内力比较接近,增量法计算的结构变形比总量法计算结果大,与实测结果更为接近。考虑土与结构共同作用,用有限差分法对衡重式桩板挡墙墙后地表沉降进行分析。墙后地表沉降与卸荷板的设置位置有关,卸荷板设置在合理位置时,墙后地表沉降为向下的抛物线,地表沉降影响范围约为1.6H,地表沉降的最大值在距离墙背0.5H的位置,地表最大沉降与墙顶位移相等。选取填方挡墙和挖方挡墙各一工程实例,对衡重式桩板挡墙的土压力、结构内力和变形进行了现场测试,实测结果验证了卸荷板的卸荷作用,其余土压力、内力和变形的实测数据与数值分析和本文分析方法计算结果接近。最后,总结了衡重式桩板挡墙的变形特性,提出了卸荷板建议取值范围及控制结构变形的建议措施。
[Abstract]:The counterweight pile plate retaining wall is a new type of retaining structure, which is composed of pile, lock beam, column plate wall and counterweight platform (unloading plate) and so on. The unloading plate with rigid connection with the wall body reduces the earth pressure acting on the lower structure of the unloading plate, and provides a reverse bending moment (relative to the moment caused by the earth pressure) for the pile, which makes the internal force distribution of the structure balanced. At the same time, the displacement trend of retaining structure leaving soil is limited. The load-deformation behavior of this kind of retaining wall is more complex than that of other kinds of pile-plate retaining wall because of the unloading action of unloading plate, the action of reverse bending moment and the interaction between structure and structure. In the previous research work, the mechanical characteristics of the structure have been deeply studied, but the deformation behavior of the retaining wall is not clear, and the deformation calculation method and the design method to control the deformation are still to be studied. This paper studies the deformation behavior of the counterweight pile plate retaining wall, puts forward the design method of deformation control, and further consummates the design theory, which has important theoretical and engineering practical significance for the further popularization and application of this kind of structure. Based on the elastic foundation beam method, the analytical analysis method of the internal force and deformation of the retaining wall of pile and plate is derived according to the "two-stage method". The calculated results of this method are compared with those of the finite element method of elastic bar system, and the calculated results are close to those of the finite element method, and compared with the results of model tests and field tests, the calculated results of this analysis method are in agreement with the measured results. The reliability and rationality of the method are verified. Using the analytical analysis method proposed in this paper, the influence of the buried depth and the width of the unloading plate on the deformation of the structure is studied. The reasonable buried depth and the position of the plate width of the unloading plate are analyzed. The results of the analysis are verified by the model test and the numerical analysis method. In addition, the effects of pile length, pile diameter and soil parameters on structural deformation are analyzed. By using FLAC software and considering the interaction of soil and structure, the numerical analysis of different construction sequence of fill retaining wall and excavated retaining wall is carried out, and the results are compared with the results of this analysis method and the finite element method of bar system. It is concluded that under the condition of considering the interaction between soil and structure, the deformation calculated by numerical analysis is relatively small, and the internal force and deformation of the excavated retaining wall calculated by incremental method and aggregate method are close to each other. The structural internal forces calculated by the incremental method and the aggregate method are close to each other, and the structural deformation calculated by the incremental method is larger than that by the aggregate method, which is closer to the measured results. Considering the interaction between soil and structure, the surface settlement behind the retaining wall of pile plate is analyzed by finite difference method. The surface settlement behind the wall is related to the location of the unloading plate. When the unloading plate is set in a reasonable position, the surface settlement behind the wall is a downward parabola, the influence range of the surface settlement is about 1.6 H, and the maximum value of the surface settlement is 0.5 H from the back of the wall. The maximum settlement of the surface is equal to the displacement of the top of the wall. The earth pressure, structural internal force and deformation of the retaining wall with counterweight pile and plate are tested on the spot by selecting one engineering example of filling retaining wall and excavating retaining wall. The measured results verify the unloading effect of unloading plate and the remaining earth pressure. The measured data of internal force and deformation are close to the results of numerical analysis and the analytical method in this paper. Finally, the deformation characteristics of the counterweight pile plate retaining wall are summarized, and the suggested range of the unloading plate and the suggested measures to control the deformation of the structure are put forward.
【学位授予单位】：中国铁道科学研究院
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU476

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