长桩基论文高速铁路桥梁长桩基础桩底压缩层厚度的研究.docVIP

长桩基论文：高速铁路桥梁长桩基础桩底压缩层厚度的研究 【中文摘要】高速铁路要求轨道结构必须具有高稳定性和高平顺性,因此对桥梁沉降控制提出了严格的要求。高速铁路桥梁长桩基的沉降计算的重要性凸显。在相关影响因素中,压缩层厚度具有重要的意义。合理确定压缩层厚度能够有效提高沉降计算的精度,进而采用合理的地基处理方法以控制沉降及工后沉降。本文依托京沪高速铁路北段DK240工点3个墩位群桩基础的9根基桩,通过理论计算、现场试验和Plaxis 3D Foundation有限元模拟开展研究,得到以下结论：在现场试验中提出了“单点沉降计和液位沉降计联合测试法”,克服了单点沉降计下端无法锚固于稳定基岩的弊端,利用单点沉降计和液位沉降计各自的优势,使得桥梁桩基在深厚软土地基中的沉降监测得以实现。通过对测得数据进行分析,得出压缩层厚度。根据沉降监测数据,修改和完善理论计算数值模型；深层压缩土层的压缩模量也是沉降计算的一个重要参数。提出了与土层深度相关的天然状态下压缩模量的计算公式。通过有限元计算得出桩底压缩层厚度。将现场实测结果与现行规范建议方法和有限元计算结果进行对比分析,得出现行规范中采用“应变控制法”确定压缩层厚度的计算结果偏于保守,建议采用10%应力比为条件的“应力控制法”计算压缩层厚度。 【英文摘要】High speed railway needs high quality of stability and regularity, and strict requirements of settlement control is asked. The settlement calculation for long piles of high speed rail-way bridge is in significance. Thickness of compression layer plays an important role. The rational determination of compression layer thickness can improve settlement calculation, so can rational ground treatment be taken to control the settlement and post-construction settlement.Based on the 9 piles in the group piles foundation of 3 piers at the DK240 work point in the northern segment of Jing-Hu high speed rail-way, through theoretical calculation, field investigation, and Plaxis 3D Foundation finite element analogy, following conclusions can be seen:In the field investigation, the method of “cooperating test using single point settlement gauge and level settlement gauge” is proposed, coming over the disadvantage that single point settlement gauge can’t be anchored in rock, making full use of single point settlement gauge and level settlement gauge, allowing settlement monitor of long group piles in deep soft soil layer. The compression layer thickness is obtained by measured data.The calculation model is revised and perfected according to the data of settlement monitoring. Compression modulus of deep compressible soil is an important parameter in the settlement calculation. A f