强夯处治粉煤灰路基的显式动力非线性有限元数值模拟
发布时间：2018-11-15 17:53
【摘要】：随着国民经济的发展，粉煤灰的排放量和堆积量逐年增加。我国工业化、城镇化的推进导致土地资源愈发紧张，大量工程不得不建立在粉煤灰堆积地区。而粉煤灰地基属于软土地基，其承载力较低，往往不能满足工程需要，因此必须对其进行处理使其满足承载力、稳定性和抗变形能力的要求。强夯法凭借其施工工艺简单、经济性好、加固效果明显等优点在粉煤灰地基处治中应用较多。 然而，与广泛的工程应用相比，强夯的理论研究稍显滞后。强夯过程的复杂性决定了其难以用精确的解析方法求解。其加固机理和设计理论方面尚不成熟，现场施工主要依靠经验公式和试验确定，大大限制了强夯法的发展和应用。而传统的数值方法均基于小变形假定，工程实际中夯击区将产生较大破坏，其结果往往不尽如人意。随着数值计算方法的发展，显式动力非线性有限元理论日趋成熟，为强夯这类非线性大变形问题的求解提供了一种新的选择。在常见土类如湿陷性黄土、碎石土、风成砂的强夯研究中，显式动力非线性数值方法已经占有一席之地，取得了一定的成果。相较而言，其在粉煤灰地基中的应用目前尚属空白。 鉴于此，本文首先综合论述了显式动力非线性有限元数值理论，并比较了显式与隐式理论的区别，然后基于显式动力非线性有限元分析方法，利用ANSYS/LS-DYNA软件对强夯问题进行分析，得出了显式动力非线性数值模拟方法的一般步骤。结合某高速公路填土路基强夯实例建立三维立体模型，对夯击碰撞过程进行数值模拟，，得到了强夯加固范围及夯后土体的应力场、位移场。通过与现场实测数据的比对，验证了显式动力非线性有限元数值模拟方法在强夯问题中的适用性。在此基础上，研究了岳阳地区强夯处治粉煤灰路基问题。通过对两种施工方案分别建模分析，对夯锤参数选取问题进行了探讨，分析数值模拟结果，比较两种方案的夯后土体沉降，得出了同能级下重锤低落距有更好的加固效果的结论。
[Abstract]:With the development of national economy, the quantity of fly ash discharge and accumulation increases year by year. Due to the development of industrialization and urbanization in China, land resources are becoming more and more tight, and a large number of projects have to be built in fly ash accumulation areas. The fly ash foundation belongs to the soft soil foundation, its bearing capacity is low, often can not meet the engineering needs, so it must be treated to meet the requirements of bearing capacity, stability and deformation resistance. The dynamic compaction method is widely used in the treatment of fly ash foundation with its advantages of simple construction technology, good economy and obvious reinforcement effect. However, compared with the extensive engineering applications, the theoretical research of dynamic compaction is slightly lagging behind. Because of the complexity of dynamic compaction process, it is difficult to solve it with accurate analytical method. The reinforcement mechanism and design theory are not mature, and the field construction mainly depends on the empirical formula and test, which greatly limits the development and application of the dynamic compaction method. However, the traditional numerical methods are based on the assumption of small deformation, and the tamping zone will be destroyed greatly in engineering practice, and the results are often not satisfactory. With the development of numerical methods, explicit nonlinear finite element theory is becoming more and more mature, which provides a new choice for solving nonlinear and large deformation problems such as dynamic compaction. In the dynamic compaction research of common soil such as collapsible loess, gravel soil and wind-formed sand, explicit dynamic nonlinear numerical method has occupied a place, and some achievements have been made. In contrast, its application in fly ash foundation is still blank. In view of this, the explicit dynamic nonlinear finite element numerical theory is firstly discussed, and the difference between explicit and implicit finite element theory is compared, and then based on explicit dynamic nonlinear finite element analysis method, The dynamic compaction problem is analyzed by using ANSYS/LS-DYNA software, and the general steps of explicit nonlinear numerical simulation method are obtained. Based on the example of dynamic compaction of embankment of a certain expressway, a three-dimensional model is established to simulate the impact process of compaction. The range of consolidation and the stress field and displacement field of soil after compaction are obtained. The applicability of explicit nonlinear finite element numerical simulation method in dynamic compaction problem is verified by comparing with field measured data. On this basis, the problem of treating fly ash roadbed with dynamic compaction in Yueyang area is studied. Through modeling and analysis of two construction schemes, the parameter selection of tamping hammer is discussed, the numerical simulation results are analyzed, and the settlement of soil after tamping is compared between the two schemes. It is concluded that the weight drop distance has better reinforcement effect at the same energy level.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1
本文编号：2334022
[Abstract]:With the development of national economy, the quantity of fly ash discharge and accumulation increases year by year. Due to the development of industrialization and urbanization in China, land resources are becoming more and more tight, and a large number of projects have to be built in fly ash accumulation areas. The fly ash foundation belongs to the soft soil foundation, its bearing capacity is low, often can not meet the engineering needs, so it must be treated to meet the requirements of bearing capacity, stability and deformation resistance. The dynamic compaction method is widely used in the treatment of fly ash foundation with its advantages of simple construction technology, good economy and obvious reinforcement effect. However, compared with the extensive engineering applications, the theoretical research of dynamic compaction is slightly lagging behind. Because of the complexity of dynamic compaction process, it is difficult to solve it with accurate analytical method. The reinforcement mechanism and design theory are not mature, and the field construction mainly depends on the empirical formula and test, which greatly limits the development and application of the dynamic compaction method. However, the traditional numerical methods are based on the assumption of small deformation, and the tamping zone will be destroyed greatly in engineering practice, and the results are often not satisfactory. With the development of numerical methods, explicit nonlinear finite element theory is becoming more and more mature, which provides a new choice for solving nonlinear and large deformation problems such as dynamic compaction. In the dynamic compaction research of common soil such as collapsible loess, gravel soil and wind-formed sand, explicit dynamic nonlinear numerical method has occupied a place, and some achievements have been made. In contrast, its application in fly ash foundation is still blank. In view of this, the explicit dynamic nonlinear finite element numerical theory is firstly discussed, and the difference between explicit and implicit finite element theory is compared, and then based on explicit dynamic nonlinear finite element analysis method, The dynamic compaction problem is analyzed by using ANSYS/LS-DYNA software, and the general steps of explicit nonlinear numerical simulation method are obtained. Based on the example of dynamic compaction of embankment of a certain expressway, a three-dimensional model is established to simulate the impact process of compaction. The range of consolidation and the stress field and displacement field of soil after compaction are obtained. The applicability of explicit nonlinear finite element numerical simulation method in dynamic compaction problem is verified by comparing with field measured data. On this basis, the problem of treating fly ash roadbed with dynamic compaction in Yueyang area is studied. Through modeling and analysis of two construction schemes, the parameter selection of tamping hammer is discussed, the numerical simulation results are analyzed, and the settlement of soil after tamping is compared between the two schemes. It is concluded that the weight drop distance has better reinforcement effect at the same energy level.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1
【参考文献】
中国期刊全文数据库 前10条
1 周健;张思峰;贾敏才;王冠英;;强夯理论的研究现状及最新技术进展[J];地下空间与工程学报;2006年03期
2 李国栋;粉煤灰的结构、形态与活性特征[J];粉煤灰综合利用;1998年03期
3 吴铭炳;王钟琦;;强夯机理的数值分析[J];工程勘察;1989年03期
4 黄瑛;;强夯对周围已建建筑物的影响[J];中国港湾建设;2007年03期
5 张雪峰;倪永军;章和庆;滕忻利;;强夯法加固高速公路路基时与临近构筑物安全距离的确定[J];公路交通科技(应用技术版);2009年01期
6 何文,钟志华;显式有限元技术在车身薄壁梁结构件数值模拟中的应用[J];湖南大学学报(自然科学版);2005年01期
7 欧阳小琴,夏为民,熊亮;粉煤灰资源综合利用的现状[J];江西能源;2002年04期
8 罗道成,易平贵,刘俊峰;我国粉煤灰综合利用的发展现状与建议[J];煤化工;2002年06期
9 张建辉;杨培轩;;强夯法处理风成砂地基的数值模拟分析[J];河北大学学报(自然科学版);2013年02期
10 费香泽,王钊,周正兵;强夯加固深度的试验研究[J];四川大学学报(工程科学版);2002年04期
本文编号：2334022
本文链接：https://www.wllwen.com/kejilunwen/jiaotonggongchenglunwen/2334022.html
