【作者】 胡云龙；

【导师】 赵有明；

【作者基本信息】 中国铁道科学研究院 ， 岩土工程， 2013， 博士

【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。更多还原

【Abstract】 Sheet pile wall with relieving platform is a new type of retaining structure, which is composed of piles, lintel beam, post-board wall, relieving platform (unloading plate) and other components. The unloading plate connected rigidly with the retaining wall reduces soil pressure applied on the substructure below the unloading plate, and provide a counter moment on the pile (relative to the bending moment caused by soil pressure). In this case, the internal force distribution on the structure is more balanced. Meanwhile, the movement of the retaining wall against soil trends to be smaller. Due to the existence of the unloading plate, the stress-deformation behavior is more complicated than other types of pile-supported retaining walls. In previous studies, the mechanical behavior has been carried out, but the deformation behavior of sheet pile wall with relieving platform is not fully revealed. The deformation calculation and controlling method need to be improved. Therefore, it is absolutely necessary to study the deformation behavior of sheet pile wall with relieving platform, propose a practical and reliable calculation method for the internal forces and deformation of the retaining structure, and refine the calculation method. This study has important theoretical and practical significance for engineering.In this paper, based on the elastic foundation beam theory, the author derived the analytical calculation method for the internal force and deformation of sheet pile wall with relieving platform using two-segment-method. The newly developed calculation method fits well with the simulation results using beam-spring FEM. Furthermore, it can be found that the calculated results in good agreement with the model test results and field test results. Thereliability and rationality of the newly developed method have been verified.Based on the analytical methods, the effects of position and width of the unloading plate on the deformation of the retaining structure were investigated. The reasonable position and appropriate width of the unloading plate were analyzed. The calculation results were confirmed using model test and numerical simulation. In addition, the effects of dimension of piles and soil properties on the deformation of the retaining structure were also studied in this thesis.Taking structure-soil as a whole, the deformation behavior of the retaining walls under different construction sequences including the fill and excavation sequences was studied using a two-dimensional elastic-plastic finite difference program named FLAC. Comparing the simulation results using beam-spring FEM with the results calculated by the newly developed method, it can be found that the deformation become smaller considering the interaction between soil and retaining structure, there is no big difference between the internal force and deformation of the excavation retaining wall using incremental and totalizing method. The deformation of the fill retaining wall calculated by the incremental method is bigger than that calculated by the totalizing method which fits well with the field test result.Considering the interaction between soil and structure, finite difference method was used to analyze the settlement behind the sheet pile wall with relieving platform. The settlement is related to the position of the unloading plate. The settlement curve is a parabolic curve if the position of the unloading plate is reasonable. The settlement is about1.6H, the maximum value appear at the position about0.5H from the wall surface, the maximum value is equivalent to the displacement of the wall head.A fill and an excavation retaining structures were selected to study the soil pressure, internal force and deformation of retaining structure on site. The field tests were employed to verify the effectiveness of the unloading plate. It can be found that the soil pressure, internal force and deformation fit well with the numerical results using the newly developed method.Finally, the author summarized the deformation characteristics of the sheet pile wall with relieving platform. The reasonable range of the position and width of the unloading plate was given for the designers. Moreover, the measures used to control the deformation of retaining structures were listed simultaneously.更多还原