水泥土半刚性挤密桩复合地基承载能力试验研究

发布时间：2018-03-01 14:29

本文关键词： 水泥土半刚性桩复合地基本构模型极限承载力　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：水泥土、灰土桩复合地基技术在西北地区被广泛的应用于提高地基承载力以及消除湿陷性,为了达到更加经济、节约资源的效果,许多外掺剂也被应用到了水泥土和灰土中来,用以提高其强度。加了各种外掺剂的水泥土和灰土填料强度一定程度上得到的提高。本文以在1:6水泥土中掺入不同含量石灰为外掺剂为例进行了为期7个月的室内试验,发现适量石灰可以提高水泥土的无侧限抗压强度、抗剪强度、黏聚力和弹性模量等参数;而过量的石灰则会抑制水泥土的无侧限抗压强度,但对其他参数的影响不大,对实际工程有重要的借鉴意义。同时,基于室内无侧限抗压强度试验的应力-应变曲线特点,推导出了加了少量石灰的水泥土的损伤本构方程和损伤演化方程,结合已有的研究成果得出该损伤本构模型和损伤演化方程还适用于水泥黄土和加了少量水泥的灰土。经验证,该公式计算结果与室内试验应力-应变曲线较为吻合,且该公式参数较少且容易获取,计算简便。基于损伤理论和桩体的损伤本构模型,修正了半刚性桩复合地基沉降计算公式,并运用该公式对已建成的西安大华公园世家9#地块1#楼的复合地基在不同荷载下的沉降量进行了计算,将计算结果与规范算法计算结果绘制成p-s曲线图,分析了该复合地基的承载能力,得出修正后的算法比规范算法计算结果精度提高了 13%。同时用FLAC3D对不同填料的半刚性桩复合地基的极限承载力进行了模拟,得到了其可能达到的最大承载力,对实际工程有一定的指导意义。
[Abstract]:The technology of cement soil, lime soil pile composite foundation is widely used in Northwest China to improve the bearing capacity of foundation and eliminate collapsibility. In order to achieve more economical and save resources effect, many admixtures have also been applied to cement soil and lime soil. In order to improve its strength, the strength of cement soil and lime soil filler with various admixtures has been improved to a certain extent. In this paper, the laboratory test was carried out for 7 months with the addition of different contents of lime as the admixture in 1: 6 cement soil. It is found that proper amount of lime can increase the unconfined compressive strength, shear strength, cohesion and elastic modulus of cement soil, while excess lime can inhibit the unconfined compressive strength of cement soil, but has little effect on other parameters. At the same time, based on the characteristics of stress-strain curve of unconfined compressive strength test in laboratory, the damage constitutive equation and damage evolution equation of cement soil with a small amount of lime are derived. Combined with the existing research results, the damage constitutive model and damage evolution equation are also suitable for cement loess and lime-soil with a small amount of cement. It is verified that the calculated results are in good agreement with the stress-strain curves of laboratory tests. Based on the damage theory and the damage constitutive model of the pile, the formula for calculating the settlement of semi-rigid pile composite foundation is modified. Using the formula, the settlement of the composite foundation of the Xianghua Park Shijia9# block of Xi'an Dahua Park under different loads is calculated, and the calculated results and the calculated results of the specification algorithm are plotted into a p-s curve. The bearing capacity of the composite foundation is analyzed, and it is concluded that the accuracy of the modified algorithm is 13% higher than that of the standard algorithm. At the same time, the ultimate bearing capacity of semi-rigid pile composite foundation with different fillers is simulated by FLAC3D. The maximum bearing capacity can be obtained, which has certain guiding significance for practical engineering.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU470

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