强夯加固深度及主满夯匹配问题的探讨

结合工程实践对强夯法处理地基的加固深度和主夯、满夯单击夯击能的匹配问题进行分析和探讨。     

强夯加固深度及主满夯匹配问题的探讨

结合工程实践对强夯法处理地基的加固深度和主夯、满夯单击夯击能的匹配问题进行分析和探讨。     

黄土地基高能级强夯室内模型试验研究

为研究高能级强夯加固黄土地基过程中的土体变形规律与加固效果,基于室内模型试验,采用多组平行试验研究了含水率、强夯能级、夯锤落距和锤径变化对高能级强夯黄土地基夯沉量的影响,并结合ABAQUS有限元软件对有效加固深度进行了计算。结果表明：黄土地基含水率为最优含水率时,高能级强夯加固效果最好;采用6 000、8 000、12 000、15 000 kN·m能级强夯加固同一黄土地基的最优夯击次数分别为13、12、10、9击;采用“重锤低夯”达到设计加固效果所需的夯击次数较“轻锤高夯”少;相较于大锤径夯锤,采用小锤径夯锤更能提升强夯加固效果;数值模拟结果与模型试验结果较为吻合,采用6 000、8 000、12 000、15 000 kN·m能级加固同一黄土地基的有效加固深度分别为8.8、9.9、11.1、12.2 m。     

强夯法在处理湿陷性黄土地基中的应用

强夯法处理湿陷性黄土地基具有施工简便、快速有效、造价经济、质量可靠的优点.它对增强地基密实度、消除土层湿陷性、降低土层压缩性和提高地基承载力效果显著.针对某仓库地基强夯工程,对强夯加固效果进行分析,采用文中建议的公式计算夯后地基承载力,理论计算值与实测值基本吻合.     

强夯在湿陷性黄土地基处理中的应用研究

本针对中川机场扩建工程中遇到的湿陷性黄土地基的处理问题,在现场选择了三个试验区,分别采用不同的夯击方案进行了试验研究,提出了切实可行的强夯处理方案,为大面积的场道地基处理提供了依据,并在实际处理中得到了应用,取得了较好的处理效果。     

强夯法处理高水位砂土地基的应用研究

从强夯的加固机理引入,对高水位砂土地区的强夯法地基处理设计、施工、检测进行了全面的介绍,提出了处理高水位砂土地区地基时的强夯施工参数;详细论述了地基夯实后的检测方法和内容;通过工程实例,验证地基处理效果,为类似工程提供参考。     

强夯法在加固饱和粉土地基工程中的应用

通过某工程实例,说明强夯法在加固饱和粉土地基中的设计和施工方法。通过现场原位测试及土工试验分析,对强夯法的地基处理效果进行了检验,对强夯法施工应注意的几个问题进行了讨论。     

强夯振动对CFG桩复合地基影响研究

通过数值模拟和理论分析等手段,利用有限元分析软件ADINA建立了强夯加固吹填土地基动力有限元分析模型,分别在1 000kN.m,2 000kN.m,3 000kN.m和4 000kN.m的夯击能作用下,通过改变夯击点与CFG桩之间的距离,确定强夯对CFG桩的破坏效应的影响因素,确定其安全距离,分析强夯振动下的破坏过程及破坏形态。     

湿陷性黄土钻孔夯扩挤密桩复合地基应用

介绍钻孔夯扩挤密桩复合地基施工参数选取、复合地基设计、挤密桩施工、施工质量检测及建筑物变形观测,通过工程实例验证,钻孔夯扩挤密桩复合地基在湿陷性黄土中能成功应用.     

湿陷性黄土地基强夯处理后地基承载力的确定

采用强夯法对湿陷性黄土地基进行处理,对强夯加固效果进行了分析。采用文中建议的公式计算夯后地基承载力,理论计算值与实测值基本吻合。     

强夯法加固地基的应用实践

强夯法是近些年出现的突破原来压实原理的一种地基处理方法,以石家庄大学(石电大)学生宿舍楼地基处理工程为基础,通过对有关数据的分析,探讨了其在提高地基承载力、消除地基土湿陷性方面的应用.     

动力排水固结法在连云港软土地区的应用研究

连云港海相软土具有含水量高、压缩性高、孔隙比高、强度低等特点,其工程性质较差,是该地区基础设计的重点和难点。结合某海相软土的加固处理工程,阐述了动力排水固结的加固机理,并对其加固效果进行了分析。检测结果显示,动力排水固结法处理连云港软粘土场地可以取得良好效果,其经验可供类似工程参考。     

梯度饱和土层的一维固结度的计算

研究了梯度饱和土层在外荷载下的固结作用,利用Biot理论给出了固结的基本微分方程,一些材料常数假设为指数模型,当梯度系数为零时,退化为一维均匀饱和土层的固结,利用分离变量等方法,得到透水和不透水边界条件下孔隙压力,给出了固结度曲线。当梯度系数不为零时,给出了梯度饱和土在外荷载下的孔隙压力,利用固结度的定义,数值算例出了梯度饱和土层的固结度变化曲线,分析和讨论了梯度系数等对固结度的影响。这些结果对地基下沉量计算和预测有一定的理论价值和意义。     

超载预压法加固软土地基原理和试验研究

在考虑软土超载预压后的次固结变形特性的基础上,推导出消除使用荷载作用下的主固结所需预压时间的公式.通过室内试验研究了不同超载量和不同超载预压时间对饱和软土次固结变形的影响,对排水固结法处理软土地基有一定的参考价值.     

Computation of one-dimensional consolidation of double layered ground using differential quadrature method

The authors give the solution to the problem of one-dimensional consolidation of double-layered ground with the use of the differential quadrature method. Case studies showed that the computational results for pore-water pressure in soil layer agreed with those of analytical solution; and that in the computational results for the interface of soil layer also agreed with those of the analytical solution except for the small discrepancies during shortly after the start of computation. The advantages of the solution presented in this paper are that compared with the analytical solution, it avoids the cumbersome work in solving the transcendental equation for eigenvalues, and in the case of the Laplace transform solution, it can resolve the precision problem in the numerical solution of long time inverse Laplace transform. Because of the matrix form of the solution in this paper, it is convenient for formulating computational program for engineering practice. The formulas for calculating double-layered ground consolidation may be easily extended to the case of multi-layered soils. Project (No. RC9609) supported by the Zhejiang Provincial Natural Science Foundation of China     

Equivalent response estimation of structural systems subjected to long-period ground motion

Long-period ground motion has become an important consideration because of the increasing number of large and long-period structures. Therefore, a thorough investigation on the formation and characteristics of longperiod ground motion is desirable for engineering applications. In this work, an analytical study is performed to examine the effect of several parameters and the combining mode for equivalent harmonic components on the dynamic response of systems. The results of the work show that the harmonic components in equivalent ground motion are evidently influenced by the intensity rise time, duration, phase and combining mode. Moreover, the long-period ground motions are simplified and simulated by separate harmonic components through proper combination. The findings of the work are believed to be useful in the selection of input ground motion in structural seismic analysis.     

Stable response of axisymmetric two-phase water-saturated soil

Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.     

Stable response of axisymmetric two-phase water-saturated soil

Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.