基于多孔介质理论的地基土变形模量估算方法

土的变形模量是基础沉降弹性分析理论所必需的基本参数,而目前我国的岩土工程勘察报告一般并不提供土的变形模量。通过对前人研究结果的总结分析,基于多孔介质理论,并考虑土的泊松比、孔隙比及土体扰动等影响因素,笔者提出了一种根据土的压缩模量估算变形模量的方法,对于应用弹性理论计算基础沉降和充分利用已有研究资料都具有实际的意义。     

堆载预压法处理吹填淤泥地基实例检验监测分析

本文通过介绍插塑料排水板堆载预压法在某大型国际集装箱码头吹填淤泥场地地基处理中的应用,提出了该地基处理方法监测成果的分析计算理论依据,总结了该地基处理方法的优点和在实际工程中的应用,具有工程应用参考价值。     

建筑物地基不均匀震陷有限元时程分析方法

根据建筑物不均匀震陷发生机制,提出了建筑物不均匀震陷二维有限元分析方法。采用了不规则荷载下土的残余应变模型及土体逐步软化模型,考虑了土、结构及地震动波形对不均匀震陷的协同作用效果,实现了对建筑物不均匀震陷的时程分析,并通过大型振动台试验对方法的可靠度进行了检验。     

试论软弱筑堤土的固结效应

根据软土的排水固结效应,分析了软土强度随固结效应的增长规律,提出了考虑固结效应的堤基加载方案。同时,结合淮河入海水道近期工程软土堤段的实测资料,分析了堤基土的固结度和强度增长规律,提出了分级填筑施工法。     

桥台地基附加竖向压应力通用计算公式

台后路堤及锥体将在桥台地基中产生附加竖向压应力,它是桥台设计中计算桥台不均匀沉降、桥台前移、桥台桩基侧压力和挠度的关键参数。根据有关力学原理,推导了任一宽度台后路基及锥体引起桥台地基附加竖向压应力的计算公式,解决了现有规范中计算桥台基底附加竖向压力方法只适用于单线铁路路基和查表内插易产生误差的缺点,并易于利用计算机编制程序进行计算。     

成层地基在轴对称荷载下的稳态振动分析

基于Biot动力固结方程,考虑了土体和水体的惯性力以及水-土耦合作用的影响,采用Hankel积分变换求解耦联合方程组,得到动荷载下饱和土Lamb问题的解答。根据下边界为不透水基岩的边界条件,获得了地基表面作用圆形轴对称周期荷载时土层应力、位移等的一般积分形式解,并利用矩阵传递法完成了对多层地基和Gibson地基的计算。通过算例研究了层厚和激振频率等对竖向位移的影响。     

Impact of seismic excitation characteristics on the efficiency of tuned liquid column dampers

Various types of passive control systems have been used to suppress the seismic response of structures in recent years. Among these systems, Tuned Liquid Column Dampers （TLCDs） dissipate the input earthquake energy by combining the effects of the movement of the liquid mass in the container, the restoring force on the liquid due to the gravity loads and the damping due to the liquid movement through orifices. In this study, the effects of seismic excitation characteristics such as frequency content and soil condition on the seismic performance of TLCDs are investigated using nonlinear time-history analyses. In this regard, among the past earthquake ground motion records of Iran, 16 records with different parameters were selected. In the structural model developed, the attached TLCD is simulated as a Tuned Mass Damper （TMD） having the same vibration period and damping ratio as the original TLCD. The numerical results show that the seismic excitation characteristics have a substantial role on the displacement reduction capability of TLCDs and they should be considered accordingly in the design of TLCDs.     

青岛前湾港软土物质成分与结构及加固方案设计

青岛前湾港地基的天然强度低 ,在外荷作用下承载力不高 ,导致地基变形较大 ,且变形稳定历时过长 ,因此必须对地基进行处理以满足设计要求。在大量的现场试验、监测结果的基础上 ,通过软土地基变形机理的分析研究 ,提出了地基处理的方案———塑料排水板法。根据软土层的物理力学指标 ,对塑料排水板的长度、间距、排列方式以及施工时间进行了设计计算。推算了地基土所能达到的固结度 ,并确定了最佳方案     

Centrifugal Modeling of an Embankment Backfilled with Lime-Stabilized Soil on Marine Clay

A centrifugal model test was performed for an embankment backfilled with lime-stabilized soil on an undisturbed marine clay foundation. During the test, in-flight photographs were captured, settlements were measured by displacement sensors, and displacement contours were obtained from the markers installed on the front face of the model foundation. These test data were analyzed and discussed in this paper. The test results show that the embankment was stable at 2 m height but ruptured during the loading from 2 to 4 m height. The ratio of the maximum horizontal displacement increment to the ground settlement increment at the embankment centerline suddenly increased during the loading from 4 to 6 m height, indicating the failure of the foundation. This result is in agreement with the observation of the centrifugal test and the calculated Terzaghi ultimate bearing capacity under an undrained condition. Considering the brittle behavior and low tensile strength of the lime-stabilized soil, it is recommended that the lime-stabilized soil should only be used for a low embankment with a height less than 2 meters.     

东南亚某国电厂软弱地基的工程特性研究

在对该电厂软弱地基测试、试验数据的数理统计分析基础上,通过进一步的理论分析及计算,系统地阐明了地基的变形及强度特性、剪切波速、振动周期、剪切模量及刚度系数等工程特性。笔者认为,在东南亚沿海地区的电力工程承包项目中,受地基条件复杂性和当地勘察技术局限性的制约,地基测试、试验数据存在系统性及收敛性等方面的问题。有效的工作方法应是,首先通过相应的数理统计分析,谨慎考察地基测试及试验数据可靠度的置信水平。据此进一步分析地基的工程特性,为工程建设项目的设计与施工提供可靠、完善的科学依据。