Vacuum Preloading Techniques - Recent Developments and Applications
Vacuum Preloading Techniques - Recent Developments and Applications
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DOI：
10.1061/40971(310)73
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发表时间：
2008-03
期刊：
影响因子：
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通讯作者：
J. Chu;S. S. Yan-S.;B. Indraratna
中科院分区：
文献类型：
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作者：
J. Chu;S. S. Yan-S.;B. Indraratna
文摘：对真空预压法的机理、工艺及应用进行了综述。简要总结了真空预压技术的一些最新进展，包括新材料的使用、方法的扩展和新的分析或数值模拟方法。自Kjellman(1952)提出真空预压的概念至今，已有56年的历史。自那时起，真空预压法已发展成为一种成熟有效的软土处理技术。这种方法已经成功地用于许多国家的土壤改良或土地复垦项目(Holtz 1975；Chen和Bao 1983；Bergado等人)。1998年；朱等人。2000年；Indraratna等人。2005)。随着新材料和新技术的融合，这种方法近年来得到了进一步的改进。本文对这一技术及其最新发展和应用作了简要的概述。在采用这种技术时，经常使用砂井和最近预制的垂直排水系统(PVD)来分配真空压力和排放孔隙水。在设计中通常使用80千帕的额定真空负荷，但有时也可能达到高达90千帕的较高真空压力。当需要高于80千帕的超载负荷时，可以应用真空和填充超载相结合的方式。对于非常软土地基的处理，真空预压法比填土堆载法更快，因为80kpa的真空压力几乎可以立即施加，而不会造成稳定性问题。真空预压法与等量荷载下的填土堆积法相比也更便宜(Chu等人。2000)。当从海床挖出的粘土泥浆用作填海工程的填料时，真空预压法也被纳入填海过程中。由于粘土浆填土太软，不能进行堆载，真空预压法是粘土浆固结的理想方法。数千公顷的土地已经被
ABSTRACT: In this paper, an overview on the mechanisms, techniques and applications of the vacuum preloading method are presented. Some recent developments in the vacuum preloading techniques, including the use of new materials, the expansion of the method, and new analysis or numerical modeling methods are briefly summarized. INTRODUCTION It has been 56 years since the idea of vacuum preloading was proposed by Kjellman (1952). Since then, the vacuum preloading method has evolved into a mature and efficient technique for the treatment of soft clay. This method has been successfully used for soil improvement or land reclamation projects in a number of countries (Holtz 1975; Chen and Bao 1983; Bergado et al. 1998; Chu et al. 2000; Indraratna et al. 2005). With the merging of new materials and new technologies, this method has been further improved in recent years. A brief overview of this technique and the recent developments and applications is given in this paper. In adopting this technique, sand drains and recently prefabricated vertical drains (PVDs) have often been used to distribute the vacuum pressure and discharge pore water. A nominal vacuum load of 80 kPa is normally used in design although a higher vacuum pressure of up to 90 kPa may be achieved sometimes. When a surcharge load higher than 80 kPa is required, a combined vacuum and fill surcharge can be applied. For the treatment of very soft ground, the vacuum preloading method is faster than the fill surcharge method, as the 80 kPa vacuum pressure can be applied almost instantly, without causing stability problem. The vacuum preloading method is also cheaper when compared with the fill surcharge method for an equivalent load (Chu et al. 2000). The vacuum preloading method has also been incorporated in the land reclamation process when clay slurry dredged from seabed is used as fill material for land reclamation. As the clay slurry fill is too soft for fill surcharge to be applied, the vacuum preloading method is ideally used for the consolidation of the clay slurry. Thousands of hectares of land have been