新型固化剂改良黄土边坡稳定性分析

发布时间：2018-10-09 11:40

【摘要】：黄土特有的高压缩性、湿陷性、强度低等不良工程特性，使得其必须经处理后方能满足高速公路、铁路路基和水利坝基等设计、施工及使用要求。工程上常见的处理方式有换填、打桩、加入固化材料等，方式多种多样，效果也各不相同。新型固化剂由于其优良的物理力学性能正在被广泛的研究并试用于基础工程中。本文采用新型高分子材料SH固化剂改良黄土，在参阅文献和室内试验的基础上，就改良黄土边坡的稳定性进行数值模拟分析研究。主要工作及取得的成果如下：（1）进行固化剂SH改良黄土相关试验和结果分析。由SH掺量和含水率对改良黄土抗剪强度的影响曲线知，固化剂SH能明显提高黄土抗剪强度，且对改良黄土黏聚力的影响要大于内摩擦角。含水率对改良黄土的抗剪强度影响显著等结论。试验数据为改良黄土边坡稳定性数值模型参数选取提供了较科学的事实依据。（2）建立BP神经网络预测模型。选取室内土工试验数据作为学习样本和测试样本，就含水率对改良黄土力学参数的影响进行了预测分析，，预测结果与试验结果基本吻合。可见将BP神经网络用于抗剪强度参数预测是可行的，从而实现了由物理指标到力学参数转化，为改良黄土性能探究提供了一种新的研究方法。（3）将强度折减法应用到大型通用有限元软件ABAQUS中，分析探讨了改良黄土的边坡稳定性，模拟了弹性模量、泊松比、加固厚度、坡角、土体重度及含水率等物理力学参数对边坡稳定性的影响。在边坡变形分析中，论证了固化剂SH加入黄土边坡表层的可行性，研究发现，含水率和土体重度对改良黄土边坡的水平位移、隆起位移及下滑位移影响较大，边坡角度、泊松比与弹性模量的影响较小；通过敏感性分析得出了固化剂SH的最优加固厚度及影响因素，模拟结果显示，含水率对改良黄土边坡安全系数的敏感度最大，其次是土体重度，弹性模量和泊松比对安全系数的敏感度较小，与边坡变形分析结论基本一致。因此在施工或者运行期间应格外重视水位变化等对边坡稳定性的影响，做好相关预防和治理工作。通过上述研究分析,得出固化剂SH应用到黄土边坡改良领域是科学合理的，研究结果对黄土边坡改良技术及黄土地区地质灾害的防治提供了理论参考价值。
[Abstract]:Because of its high compressibility, collapsibility and low strength, loess must be treated before it can meet the design, construction and application requirements of expressway, railway subgrade and water conservancy dam foundation. The common treatment methods in engineering are filling, piling, adding solidified materials and so on. Because of its excellent physical and mechanical properties, the new curing agent is widely studied and used in foundation engineering. In this paper, a new polymer material, SH curing agent, is used to improve loess. On the basis of literature and laboratory tests, the stability of improved loess slope is studied by numerical simulation. The main work and results obtained are as follows: (1) relevant experiments and results analysis of SH curing agent for loess improvement are carried out. According to the influence curve of SH content and moisture content on the shear strength of improved loess, the curing agent SH can obviously improve the shear strength of loess, and the influence on the cohesion of improved loess is greater than that of internal friction angle. The effect of moisture content on the shear strength of improved loess is significant. The experimental data provide a scientific basis for the selection of the parameters of the numerical model for improving the stability of loess slope. (2) the prediction model of BP neural network is established. The influence of moisture content on the mechanical parameters of improved loess is predicted and analyzed by using the data of indoor geotechnical test as the learning and testing samples. The predicted results are in good agreement with the experimental results. It can be seen that it is feasible to apply BP neural network to predict the shear strength parameters, thus the conversion from physical index to mechanical parameter is realized, which provides a new research method for improving loess performance. (3) the strength reduction method is applied to the large scale finite element software ABAQUS. The stability of the improved loess slope is analyzed and discussed. The elastic modulus, Poisson's ratio, reinforcement thickness and slope angle are simulated. The influence of physical and mechanical parameters such as soil weight and moisture content on slope stability. In the analysis of slope deformation, the feasibility of adding SH to the surface layer of loess slope is demonstrated. It is found that the moisture content and the soil weight have great influence on the horizontal displacement, uplift displacement and glide displacement of the improved loess slope, and the slope angle. The influence of Poisson's ratio and elastic modulus is small, through sensitivity analysis, the optimum reinforcement thickness and influencing factors of curing agent SH are obtained. The simulation results show that the sensitivity of moisture content to the safety factor of improved loess slope is the greatest, followed by the serious soil mass. The sensitivity of elastic modulus and Poisson ratio is relatively small, which is consistent with the conclusion of slope deformation analysis. Therefore, during construction or operation, we should pay special attention to the influence of water level change on slope stability, and do a good job of prevention and treatment. Through the above research and analysis, it is concluded that the application of SH to loess slope improvement is scientific and reasonable, and the research results provide theoretical reference value for loess slope improvement technology and the prevention of geological disasters in loess area.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU444;TU43

【参考文献】