【作者】 赵心涛；

【导师】 薛守义； 李晓静；

【作者基本信息】 山东建筑大学 ， 岩土工程， 2010， 硕士

【摘要】 山东省的黄河泛滥影响地区主要由黄河冲积而成,地表沉积了10m左右厚的泛滥沉积物,形成了特殊的黄河泛滥区的地质地貌条件,是我国一种特殊的区域性土,这类沉积物以粉土、粉细砂为主,并夹有软土,结构松散,强度低,是工程建设的不良地基。在黄泛区,高等级公路大量投入使用,但是地下水位的反复升降和交通荷载的振动作用,引起了饱和粉土地基的液化及不均匀沉降,导致路面开裂、破损,严重影响了路面的使用状况,大大增加了养护维修费用,若遇地震作用,液化问题将更加突出,所以,粉土液化成为一个亟待解决的问题。因此,本文针对黄泛区饱和粉土地基的液化问题,展开系统而深入的研究,采用室内试验和现场试验、数值分析相结合的方法,对黄泛区饱和粉土的动力特性和饱和粉土地基的液化性能进行了研究。主要工作有以下几个方面：(1)介绍了黄河泛滥影响区饱和粉土的工程地质特征。根据黄泛区饱和粉土含水率试验、颗粒级配试验、界限含水量试验和击实试验等的结果,分析了黄泛区粉土特殊的物理力学性质,为研究液化问题奠定了基础。(2)通过动三轴试验,研究了黄泛区饱和粉土的动力强度特性,分析得出密实度、粘粒含量的多少是影响黄泛区饱和粉土动强度的重要因素。(3)运用FLAC-3D软件对在地震荷载作用下的黄泛区饱和粉土地基进行数值模拟,地基的表层粉土层发生液化的可能性较小,沿地基深度的增大发生液化的可能性增大,这说明地基强夯加固深度范围内,因为动力压实的作用,密实度增大,提高了该区域的动强度,从而提高了该土层的抗液化能力,为强夯法地基处理技术在黄泛区的普及提供了理论基础。本论文的研究成果对黄河泛滥影响地区的高速公路在地震、车辆动荷载作用下的地基液化发展过程与变形的科学预测具有一定的指导意义,对道路的地基处理具有工程实践意义,对车辆动荷载作用下的地基变化研究具有促进作用。更多还原

【Abstract】 The Yellow River flood area in Shandong Province whose surface is deposited by flood sediments which is about ten meters thick is formed mainly alluvial deposits of Yellow River. The flood sediments is mainly constituted of silt and fine sand, forming special geological conditions in this area. The regional foundation which is loose and low intensity is bad in construction.The highways are widely applied in the Yellow River flood area,but some of their sueface crake and fail to work because of the liquefaction and differential settlement induced by variation of groundwater level and impaction of vehicle’vibration.In case of earthquake, liquefaction will become more prominent.Therefore,it seriously influences application and increases maintaining expenses.The liquefaction of silt is a serious problem to be solve.In this paper,the liquefaction of saturated silt ground was studyed systemly and deeply.The dynamic characteristics of saturated silt in the Yellow River flood area was also studyed. The laboratory test, field test,and the numerical analysis methods were used in the article. The primary studies listed bellow were carried out:(1)The engineering geological characteristics of saturated silty soil was introduced.The special physical and mechanical properties of silt in the Yellow River flood area was analyzed which is the basis to study the liquefaction by the moisture test,particle size distribution test,limit water test and compaction test we had done in the Laboratory.(2)This paper introduced the dynamic characteristics of saturated silt in the Yellow River flood area were studyed by triaxial test. From the results we knew that the density and the amount of clay content were important factors that affected the dynamic strength of saturated silty soil in this area.(3)The saturated silt ground in this area which was exerted by seismic loads was simulated numerically by using FLAC-3D. Liquefaction in surface of powder foundation occurred less likely and with the increasing depth of foundation it occurred more likely. The density of soil in upper layer increased because of the role of dynamic compaction. And as density increased, the dynamic strength of soil in this region improved,thus improving the soil liquefaction resistance.It provides a theoretical basis for the popularity of dynamic compaction in the Yellow River flood areas.The paper has some guidance significance for the liquefaction of foundation under the effect of vehicle dynamic load in in the Yellow River flood areas and scientific forecast of transmutation, possesses engineering practice importance for road foundation treatment, and is provided with promotion effect for the study of foundation soil changes under the effect of vehicle dynamic load.更多还原