真空联合堆载预压法处理软土关键技术与评价

真空联合堆载预压法是软土路基加固处理的一种方法,具有真空预压和堆载预压的双重效果。详细阐述了真空联合堆载预压法工程应用过程中的关键技术,论述了真空联合堆载预压法的优点,并通过工程实例对真空联合堆载预压法的工程效果进行了分析,可为类似工程作参考。     

真空联合堆载预压法加固软土路基的应用

真空联合堆载预压法因其各方面的优势,在我国软土分布地区得到了广泛的应用,在某高速公路软土路基试验段中采用了真空联合堆载预压方法取得了良好的工程效果。文章以该工程的施工实践为基础,介绍了真空联合堆载预压法的主要技术参数,施工工艺和质量控制措施等。     

真空联合堆载预压法土体稳定性分析

探讨真空联合堆载预压法加固机理的特点，指出抽真空加速土体固结排水，有利于土体稳定，因此堆载速度更快，施工工期更短，对施工过程中控制土体堆载速度有重要参考意义。     

堆载联合真空预压排水固结法加固沿海软弱地基

堆载预压法和真空预压法同属排水固结法,二者各有优缺点,文中结合工程实例较详细地论述了堆载预压和真空预压联合加固软基的原理及施工要点。     

真空-堆载联合预压法在高等级公路软基加固处理中的应用探讨

本文简述了真空-堆载联合预压法加固机理,并结合工程实例,详细阐述了真空-堆载联合预应法加固处理软土路基施工技术,并对现场监测成果和加固处理效果进行了分析和评价。     

真空-堆载联合预压法在高等级公路软基加固处理中的应用探讨

本文简述了真空-堆载联合预压法加固机理,并结合工程实例,详细阐述了真空-堆载联合预应法加固处理软土路基施工技术,并对现场监测成果和加固处理效果进行了分析和评价。     

真空堆载联合预压法在公路软基处理中的应用

首先介绍了真空堆载联合预压法的加固机理,然后结合高速公路软基处理中真空堆载联合预压法的应用,分析了对该类工程的加固效果,认为真空堆载联合预压法施工工艺成熟、能增加地基稳定性、缩短施工工期,可作为高速公路软基处理的一种手段进一步推广。     

高速公路软基加固工程试验段真空联合堆载预压施工技术分析

本文结合工程实例,介绍真空联合堆载预压法处治公路软基的施工技术。重点分析该技术处理软土路基的施工工艺;并对真空联合堆载预压质量进行了检验,结果表明该技术加快了软基排水固结的速度,使软基工后沉降得到有效控制,对类似工程施工具有参考价值。     

真空-堆载联合预压处理效果的关键因素研究

本文参阅八十年代初至二十世纪末国内外广泛应用的真空一堆载联合预压法技术，结合广东省多条高速公路的实践经验，综合考虑了地质条件、软土地基处理情况、施工情况、工后观测情况等各方面因素，选取若干个断面对比分析，对真空联合堆载预压法加固效果进行了具体分析，从密封性、竖向排水体的长度、真空一堆载满载的时间三个方面重点阐述了影响真空预压处理效果关键因素及对策。     

真空联合堆载预压法在路基处理中的应用

介绍了真空联合堆载预压法在公路工程中的应用,根据施工实例介绍了真空联合堆载预压的设计及施工,并对地基处理施工效果进行了总结。真空联合堆载预压加固施工是一种快速、简便、文明的加固地基的有效方法,能够有效地加速深厚软土地基的排水固结.减少工后沉降。水平向位移是真空预压施工中容易出现的问题,因此真空预压施工在设计及施工时要考虑对周围建筑结构的影响。真空预压施工有投资大的缺点,这是阻碍其大力推广的主要原因。     

Experimental study on a dredged fill ground improved by a two-stage vacuum preloading method

The vacuum preloading method has been wisely chosen among many ground-improvement methods considering the time limit of many projects and the characteristics of reclaimed soil. However, the loss in vacuum with soil depth, the clogging around prefabricated vertical drains (PVDs), and the deteriorative consolidation of the deep soil layer, among other factors, create a large challenge to vacuum preloading for dredged marine clay fill. Thus, this study proposes a two-stage vacuum preloading method and focuses on its feasibility and effectiveness. Contrasting laboratory tests are performed in two identical experimental tanks with dredged marine clay fill from the Wenzhou land reclamation site in China. In one tank, the one-stage vacuum preloading method is used to serve as a baseline for this study. In the other tank, use of the two-stage vacuum preloading method is proposed for consolidation; it comprises two stages. In the first stage, the dredged marine clay fill is conditioned by vacuum preloading using half of the PVDs, where the dissipation of the excess pore water pressure tends to be steady. In the second stage, vacuum preloading is activated using all the PVDs. The results show that a better consolidation effect is achieved with the proposed method in terms of the settlement, vacuum pressure, pore water pressure, water content, vane shear strength, and soil particle microstructure after soil consolidation.     

A pilot test on a membraneless vacuum preloading method

A membraneless vacuum preloading method is proposed in this paper for soft soil improvement. The method offers several advantages over the conventional vacuum preloading in which membrane is used to create the airtight condition and sand blanket layer to distribute vacuum. To assess the effectiveness of the proposed method, a pilot test was conducted at a land reclamation site in Tianjin, China. The ground settlement and the pore water pressure (PWP) at different elevations in soil were measured. After vacuum preloading, the average water content of the soft soils reduced by approximately 12% and the undrained shear strength increased twofold. The average degree of consolidation at the end of the vacuum preloading achieved 85.1% based on the settlement data and 84.5% based on the PWP data. The pilot test data have shown that the proposed method exhibits similar efficiencies to the conventional vacuum preloading method.     

超载真空预压动力排水固结联合法运用实例

结合汕头市东部城市经济带市政基础设施建设项目试验段某区软基处理工程实例,介绍了超载真空预压动力排水固结联合法,通过检测结果表明,采用超载真空预压动力排水固结联合法能够有效加速软土固结,减少软土工后沉降。     

水下真空预压的加固机理分析

通过对水下真空预压模型试验结果的分析,提出了水下真空预压的加固机理,为该工法的实施奠定了理论基础。水下真空预压的预压荷载等于预压前的孔隙水压力和预压后(完全固结)的孔隙水压力之差,当膜下砂垫层中的孔隙水压力小于0时,膜上水可全部作为预压荷载起作用。     

真空预压法施工流程概述

在介绍真空预压加固原理的基础上分析了真空预压的特点,指出真空预压法在施工、工期和加固效果等方面优于堆载预压,对真空预压的施工工法和流程作一系统性的概述,分析了各个施工阶段需要注意的事项,可为以后真空预压的施工作一参考。     

堆载预压与真空预压加固软土地基机理的比较分析

根据有效应力原理,从土体应力路径的角度研究了堆载预压与真空预压加固软土地基的机理。通过研究可以发现：堆载预压时土体应力状态介于K0与Kf线之间而真空预压时土体的应力状态介于p轴与K0线之间。应力路径的差别表明：为防止堆载预压引起土体破坏,必须控制加载大小和速率,而真空预压加固时不会引起土体破坏。堆载预压时土体变形表现为垂直向收缩而水平向伸长的剪切变形,真空预压时土体变形主要是收缩变形并且垂直向收缩量大于水平向收缩量。在有效大主应力相同的条件下,真空预压比堆载预压的加固效果好。     

真空预压与堆载预压加固软基的微观效果评价

本文以某高速公路路基软土为研究对象,在地质条件相近的、不同试验路段的软基加固方法（堆载预压、真空预压、真空．堆载联合预压）前后（加固时间达到3个月）,工程单位分别进行了原位试验并采取软土样,开展了室内物理力学试验。结合工程单位所取的软土样进行了软土的微观结构试验,在试验的基础上,获得了软土在天然状态以及3种不同工况下的微结构图像,通过对图像处理得到加固前后的微结构特征参数。研究得出：在工程地质条件相近以及加固时间相同的情况下,无论是从宏观、微观结构,还是从固结过程和强度的增长上来看,3种工况的加固效果依次为：堆载预压→真空预压→真空．堆载联合预压。     

真空-堆载联合预压加固软基简化计算方法

在深入了解真空预压机理和砂井地基固结理论的基础上 ,根据固结度等效的原则 ,推导了与单井固结理论等效的成层均质地基等效渗透系数 ,从而将复杂砂井地基转化为无砂井成层地基 ,以达到简化计算的目的 ,并结合真空-堆载联合预压的加固特点 ,提出一种简化的真空-堆载联合预压法的有限元计算方法 ,并结合工程实例对简化方法的可靠性进行了研究 ,通过与实测资料和常规砂井地基有限元计算值对比 ,表明该简化方法具有较高的准确性 ,可方便地应用于工程设计和实践。     

真空预压施工加固软土地基效果分析

结合工程实例,对真空预压处理软基的地表沉降和土体空隙水压力监测数据进行了分析,并对地基加固效果进行了评价。结果表明真空预压法加固软土地基是非常有效的。     

Laboratory tests of electro-osmotic consolidation combined with vacuum preloading on kaolinite using electrokinetic geosynthetics

Laboratory tests were conducted on kaolinite to investigate the effectiveness of electro-osmotic consolidation combined with vacuum preloading using electrokinetic geosynthetics (EKG). The results showed that the combined method could remove more water and induce larger surface ground settlements compared with the traditional vacuum preloading or electro-osmotic consolidation. Vacuum preloading was quite effective during the first 4?h, though the electro-osmotic consolidation took a main role in dewatering process after 9?h. The combined method could also hinder the development of cracks, induce higher negative pore water pressure and hence increase the efficiency of electro-osmotic consolidation. The results showed that deep electro-osmotic consolidation technique combined with vacuum preloading could result in significant water removal efficiency along with shorter electrode length. Furthermore, both electro-osmotic consolidation and the combined method could consolidate the soil efficiently with low energy consumption.