南疆盐渍土路基盐-冻胀变形综合防治技术研究

盐渍土盐-冻胀变形对新疆南疆地区的道路路基造成了不同程度的破坏,尤其对南疆新建城市阿拉尔市和图木舒克市的城市道路造成了严重的变形破坏.根据南疆盐渍土工程性质及盐-冻胀变形试验研究结果,作者总结提出了"一个加强、两个严格、三个注重"的盐渍土路基盐-冻胀变形综合防治原则和"五步骤"综合防治技术与工程措施,在南疆阿拉尔市胜利...     

The transfer matrix method applied to steel sheet pile walls

This paper proposes two subgrade reaction models for the analysis of steel sheet pile walls based on the transfer matrix method. In the first model a plastic hinge is generated when the maximum moment in the retaining structure is exceeded. The second model deals with a beam with an asymmetrical cross‐section that can bend in two directions. In the first part of this paper the transfer matrix method is explained on the basis of a simple example. Further the development of two computer models is described: Plaswall and Skewwall. The second part of this paper deals with an application of both models. In the application of Plaswall the effect of four current earth pressure theories to the subgrade reaction method is compared to a finite element calculation. It is shown that the earth pressure theory is of major importance on the calculation result of a sheet pile wall both with and without a plastic hinge. In the application of Skewwall the effectiveness of structural measures to reduce oblique bending is investigated. The results are compared to a 3D finite element calculation. It is shown that with simple structural measures the loss of structural resistance due to oblique bending can be reduced. Copyright © 2003 John Wiley & Sons, Ltd.     

瞬态瑞利波检测法在铁路路基软弱层检测中的应用

研究了瞬态瑞利波法在铁路路基检测方面应用的理论基础并结合宁沪铁路某段检测的应用效果 ,说明瑞利波法在评价路基强度、探测路基软弱层是非常有效的 ,同时其安全准确、快速经济的优点 ,也为路基检测提供了方便。     

FUZZY ISODATA聚类法在地下水水化学分类中的应用

本文以杜热草场水化学资料为例,运用FUZZY ISODATA聚类方法对地下水水化学类型的划分进行了初步研究,并与传统的舒卡列夫法和基于模糊关系聚类法所得结果进行了对比,说明了本方法的可靠性。文中运用该法对研究区水化学成份划分的五种类型,基本符合本区地下水化学成份形成与分布规律,分类合理,计算简便,特别是对水化学成份差别不大的地区更为适用。     

Modelling of earth and water pressure development during diaphragm wall construction in soft clay

The influence of a diaphragm wall construction on the stress field in a soft clayey soil is investigated by the use of a three‐dimensional FE‐model of seven adjacent wall panels. The installation procedure comprises the excavation and the subsequent pouring of each panel taking into account the increasing stiffness of the placed fresh concrete. The soft clay deposit is described by a visco‐hypoplastic constitutive model considering the rheological properties and the small‐strain stiffness of the soil. The construction process considerably affects the effective earth and pore water pressures adjacent to the wall. Due to concreting, a high excess pore water pressure arises, which dissipates during the following construction steps. The earth pressure finally shows an oscillating, distinct three‐dimensional distribution along the retaining wall which depends on the installation sequence of the panels and the difference between the fresh concrete pressure and the total horizontal earth pressure at rest. In comparison to FE‐calculations adopting the earth pressure at rest as initial condition, greater wall deflections and surface ground settlements during the subsequent pit excavation can be expected, as the average stress level especially in the upper half of the wall is increased by the construction procedure of the retaining structure. Copyright © 2004 John Wiley & Sons, Ltd.     

浅埋红层软岩隧洞围岩变形特征试验研究

红层软岩隧洞围岩变形破坏特征及其治理一直是工程界关心和亟待解决的问题.以某工程试验平硐为基础,利用隧洞围岩收敛变形监控量测及二次应力场测试,获取隧洞围岩动态综合信息,研究浅埋红层软岩隧洞无支护条件下,围岩的收敛变形和应力变化特征.结果显示,浅埋红层软岩隧洞收敛变形和二次应力之间有较好的对应关系,即较高应力对应较大的收敛变形,同时收敛变形和二次应力与埋深有较好的对应关系,且红层软岩在埋深较浅的条件下也具有流变性.在埋深较浅时,隧洞围岩与上覆岩层的接触关系会影响隧洞的应力状态及开挖后的收敛变形特征.     

镇江市软弱地基特征研究

根据4000多个工程地质勘察钻孔资料,并收集大量建筑地基基础处理实例资料,对镇江市软弱地基进行了分类,给出了软弱地基的分布范围、工程特性指标及处理方法,旨在合理利用软弱地基,确保建筑物的安全运行。     

地震作用下含暗穴高边坡黄土路基稳定性分析

黄土暗穴是一种黄土高原地区发育的特殊的不良地质现象,已经成为我国黄土地区公路破坏的主要原因之一。黄土具有极高的动力易损性,在深入研究黄土暗穴发育特点的基础上,采用有限元法对其在地震力作用下的致塌机理进行了数值模拟,得出了无暗穴、拱形暗穴和三角形暗穴3种类型高边坡黄土路基在地震荷载作用下的动力响应规律,分析了暗穴对高边坡黄土路基的地震动放大效应。结果表明:黄土暗穴的存在具有地震动放大效应,在相同洞径和埋深条件下,拱形暗穴比三角形暗穴对高边坡黄土路基的水平加速度峰值的放大效果更为明显,尤其在坡肩和洞顶放大更为显著,说明黄土暗穴的存在对高边坡黄土路基存在不利影响,易在地震作用下发生坍塌破坏。     

后压浆灌注桩在天津超高层建筑基础中的应用分析 张慧

阐述了后压浆技术补强灌注桩的基本原理,并以中海公园城项目为例,介绍后压浆灌注桩在天津软土地区超高层建筑基础中的实践应用,最后通过静荷载实测数据对比分析后压浆灌注桩在提高承载力和降低成本方面的优越性。     

黄土路基客运专线沉降监测技术研究

客运专线路基作为轨道结构的基础,其沉降监测及工后沉降预测非常关键。必须对沉降观测资料进行分析以预测工后沉降、确定无碴轨道铺设时间。本文以西宝客运专线为例对黄土路基工程沉降监测工作进行了论述。