考虑空洞影响的条形地基极限承载力

发布时间：2018-01-22 01:44

本文关键词： 空洞条形基础极限承载力破坏模式修正系数　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：作为土力学的三大经典问题之一,地基承载力不论在解析计算方面还是在试验研究方面,都有较为成熟的研究成果,而且有诸多的计算公式供使用、参考。但是随着大量工用、民用建筑的兴建,在土木工程的设计和施工中越来越多地遇到地下含有空洞的情况。当地基中出现空洞时,地基极限承载力的确定就变得相当复杂。由于地基稳定性与建筑物以及人民生命、财产的安危息息相关,所以有必要对含空洞地基的极限承载力进行深入研究。本文结合国内外研究现状,采用了一种新的计算方法即非连续布局优化方法(DLO法)对含空洞的条形地基的极限承载力进行了较为系统的研究。由于DLO方法是通过对全局范围内所有节点间的连线来搜寻、确定最终的滑移线,故该方法得到的地基破坏模式更为合理,得出的极限承载力值较传统的解析计算法更为接近真实解。本文对采用的研究手段和计算原理进行了阐述,并论证了DLO方法在含空洞地基承载力研究方面的适用性。经过大量的破坏形态模拟,本文较详细探究了空洞形状、大小、埋深以及地基土体的强度参数对地基破坏模式的影响,验证了含空洞地基的大致三种破坏模式,且随着上述各变量的改变,破坏形态彼此间可以相互转化。此外,本文在大量数值模拟的基础上,得到了多种工况下含空洞的条形地基的极限承载力值,在此基础上较细致地分别分析了各变量对极限承载力值的影响程度,认为空洞洞径与承载力成负相关,而空洞埋深、偏心距、地基土强度和承载力成正相关。在数值计算的基础上,本文提出了含空洞条形地基极限承载力的一种计算方案,即在通用的无洞地基承载力计算公式的基础上分项乘以考虑空洞影响的修正系数。该修正系数是利用线性叠加原理逐项计算而得到的。各工况下的修正系数制成了查找图表,并经过和其他文献计算结果以及软件模拟结果的比对,验证了其合理性。
[Abstract]:As one of the three classical problems in soil mechanics, the bearing capacity of foundation has been studied in both analytical calculation and experimental research, and there are many formulas for calculation. But with a lot of work and construction of civil buildings, more and more underground cavities are encountered in the design and construction of civil engineering. The determination of the ultimate bearing capacity of the foundation becomes very complicated. Because the stability of the foundation is closely related to the life of the building and the people, the safety and security of the property is closely related. Therefore, it is necessary to study the ultimate bearing capacity of the foundation with cavities. A new method, discontinuous layout optimization method (DLO), is used. The ultimate bearing capacity of strip foundation with voids is studied systematically. Because the DLO method is to search the connections between all nodes in the global scope. The final slip line is determined, so the failure mode of the foundation obtained by this method is more reasonable. The value of ultimate bearing capacity obtained is closer to the real solution than the traditional analytical method. The applicability of DLO method in the study of bearing capacity of foundation with cavities is demonstrated. Through a large number of simulation of failure patterns, the shape and size of cavities are discussed in detail in this paper. The influence of buried depth and the strength parameters of foundation soil on the failure mode of the foundation verifies the three failure modes of the foundation with cavities, and with the change of the above variables. In addition, based on a large number of numerical simulations, the ultimate bearing capacity of strip foundation with voids under various working conditions is obtained. On this basis, the influence of each variable on the ultimate bearing capacity is analyzed in detail. It is considered that the cavity diameter is negatively correlated with the bearing capacity, while the cavity depth and eccentricity. The strength and bearing capacity of foundation soil are positively correlated. On the basis of numerical calculation, a calculation scheme for ultimate bearing capacity of strip foundation with voids is proposed in this paper. That is, on the basis of the general formula for calculating the bearing capacity of the foundation without holes, the modified coefficient is multiplied by the correction coefficient which takes into account the influence of the cavity. The correction coefficient is calculated item by item by using the principle of linear superposition, and the correction coefficient under each working condition is made. Look up the chart. The rationality is verified by comparing the results with other literatures and software simulation results.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU470

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