饱和粉土的孔压和液化特性研究

对苏北地区典型的粉土进行试验研究,分析了饱和粉土的孔压发展规律和液化特性。探讨了不同因素对粉土液化特性的影响和变化规律,并对粉土和砂土的孔压变化规律进行了对比,得出粘粒含量越多粉土的液化势越高的结果;两者在施加循环应力后,孔压的的变化呈不同的发展趋势;同时提出了粉土孔压数值模型。     

南京长江四桥北锚锭基础施工方案

以南京长江四桥北锚碇基础为例,介绍大型沉井在岩面倾斜、高差大、地层性质不均,砂土液化严重以及施工场地狭小的条件下施工的方法和经验。     

氢气储存方法的现状及发展

氢能是21世纪主要的新能源之一。本文介绍了几种常用的储氢技术如高压压缩储氢技术、液化储氢技术和金属氢化物储氢技术等的研究进展,比较了各种储氢的优缺点,并对规模储氢技术的发展前景进行了预测和展望。     

毛乌素沙漠边缘湿软地基工程地质性质的研究

通过对陕西靖边至王圈梁地区地基土的颗粒成分、物质组成等物理性质和力学性质的研究,对公路沿线湿软地基的工程地质性质有了一个较全面的认识,得出该区地基具轻微盐渍化,液化严重,天然承载力低等特点,这对在建的高速公路建设具有重大的指导意义。     

Determination of the transportable moisture limit of iron ore fines for the prevention of liquefaction in bulk carriers

In 2013, over 500 million metric tons of Iron Ore Fines (IOF) were transported around the world using bulk carriers. Under certain conditions IOF, while being transported, can possibly undergo liquefaction. Since 2006, there has been eight reported bulk carrier casualties possibly caused by the liquefaction of IOF. The objective of this study is to evaluate, compare and verify the limitations and relevance of the Proctor/Fagerberg, Flow Table and Penetration test methods that are used to determine the Transportable Moisture Limit (TML) of IOF. The TML is the maximum gross water content that bulk cargoes, including IOF, may contain while being transported at sea without being at risk of liquefying. A thorough literature review, along with laboratory research, was carried out to compare the TML results from the three leading test methods to determine whether they produce reliable results when testing IOF. The study concludes that the three test methods, as stated in the 2012 International Maritime Solid Bulk Cargoes Code, are unverified and therefore not appropriate for testing IOF. This is due to the variation in the results produced by the three test methods and also due to the difference in the physical properties of IOF when compared with the materials that were originally intended for testing. It is noted that the TML alone may not control the potential liquefaction of IOF and further studies, regarding the physical properties and system variables, which cause the material to liquefy, are required to determine the liquefaction potential of IOF.     

岩溶地区钻孔灌注桩基施工技术探讨

文章以京福国道主干线福建邵武沙塘隘-三明际口高速公路下村特大桥钻孔灌注桩施工为例,结合桥位处工程地质的特点,从施工方案的选择和确定,桩基质量检测控制等方面,介绍了岩溶地区钻孔灌注桩的施工技术处理方法。     

广深港高速铁路狮子洋隧道减振无砟轨道对周边软土地层影响分析

为防止高速列车振动引起广深港高铁狮子洋大断面盾构水底隧道软土地层液化风险,轨道结构采用减振板式无砟轨道。为考察减振措施效果,分别建立列车-轨道模型、隧道-地层有限元模型,分析列车荷载作用下隧道结构及周围土层动力响应及分布规律,对比分析减振和非减振两种工况下地层动剪应力和加速度,结果表明,采取减振措施可有效降低软土地层液化风险,提高安全储备,达到了预期的目标。研究成果对隧道穿越软土地层设计具有指导意义。     

Seismic response of subsea structures on caissons and mudmats due to liquefaction

This paper presents a numerical study to investigate the seismic behavior of mudmat and caisson foundations supporting subsea structures, such as manifolds, in liquefiable sand. In seismic areas, substantial earthquake loads can be imparted to subsea structures during ground shaking, threatening their stability. In particular, soil liquefaction in sandy soil arising from strong ground motions could significantly influence the performance of subsea structures founded on liquefiable sand. The results of this study can provide a better understanding of the response of subsea manifolds in liquefiable soil during and after the earthquake. Three-dimensional, non-linear, dynamic analyses are performed using a finite difference scheme, and the ability of the model to reproduce the site response of a saturated sand deposit is assessed using the results of available centrifuge data. This study includes six computational models representing manifolds with different sizes and weights supported by caissons and mudmats in shallow and deep liquefiable sand subjected to moderate and strong earthquake shakings. The response is evaluated in terms of excess pore water pressure generated in the soil medium and displacements of the subsea foundation during and after the shaking. The results show that manifolds may experience considerable movement during liquefaction and post-liquefaction settlements. In addition, depending on the characteristics of the seismic motion and structural system, the manifold could also experience large tilting.     

浅谈液化土地基处理技术

地基土液化是一种特殊的工程地质现象，如何对地基土液化进行处理是保证公路路基稳定的条件，根据地基土液化的形成条件及工程特性浅谈对地基土液化的几种施工处理方法。     

压砂法施工沉管隧道砂垫层的抗液化研究

沉管隧道砂垫层基础的抗液化问题是沉管地基处理关键技术之一。地震砂土液化是一个实际工程问题,一旦发生液化会给地下工程结构带来巨大灾害。我国的水工建筑物抗震设计规范规定了饱和砂土在不同地震烈度时可能发生液化的相对密度值。但由于沉管隧道砂垫层基础是在水下施工,施工时相对密实度不易控制,如果按规范取值会偏大,造成巨大浪费。本文通过对沉管隧道砂垫层抗液化分析并结合工程实例提出了砂垫层施工时应达到的合理密实度。