含竖向排水体的软土路基固结分析

对含竖向排水体地基的固结理论进行了分析,研究了加载模式、竖向排水体间距及直径对软土路基固结的影响。结果表明,通过超载预压或者真空堆载联合预压可以较快地使软土固结,有利于减小工后沉降。     

辽宁滨海大道软基处理实例和效果分析

辽宁滨海大道是辽宁省沿海公路。沿线均为软土地基,采用土工布+砂垫层+塑料排水板+超载预压排水固结方法处理。针对滨海软土地基处理的特殊性,提出在软土地基处理过程中进行施工监测。通过连续、不间断的动态沉降观测和对资料的及时统计分析,以指导施工、验证并完善设计。最后对软土地基加固处理效果进行了检验。     

应用袋装砂井和土工布处理桥头软土路基

结合广珠东线软土路基施工实践，提出了用袋装砂井排水固结和土工布横向加筋的施工方案，并就其施工工艺作了阐述，取得了较满意的效果。     

浅析2D工法地基处理技术

复合地基技术在软土地基处理上已有着大量的应用研究,不同的处理技术适用于不同的条件。软基处理中最为常用的是粉喷桩复合地基,该法对于工期紧,软土性质较差的地基有着较理想的处理效果,但是粉喷桩在处理软土地基中常出现一些问题。粉喷桩与排水固结法有机地结合起来,成为一种全新的软土地基处理技术-排水粉喷桩复合地基工法（简称2D工法）。比较粉喷桩处理软土地基,这种技术有效地解决了传统地基处理方法遇到的问题。现在复合地基处理技术已经日趋完善,排水粉喷桩复合地基处理技术处于起步阶段,各方面的理论都不够成熟,而且还没有很好应用于工程实践中,在以后地基处理技术的完善中一定能得到进一步的发展和广泛的应用。     

塑料排水板堆载预压处理高速公路软基的研究

通过采用塑料排水板堆载预压处理高速公路软土地基4年多的现场试验,对路堤填筑及预压过程中的地表沉降、横向差异沉降、深层沉降、孔隙水压力及深层水平位移进行了分析,结果表明,采用塑料排水板堆载预压处理高速公路软土地基,在软土较浅、路堤填高不大的常规工期条件下,可以满足一般路段工后沉降的要求。     

土工织物加固软土路基效果分析

1引言虽然土工织物在软土路基的加固中得到了广泛的应用,但该技术的设计理论及计算方法还不成熟,远远落后于工程实际的需要[1]。实际工程分析中,通常采用传统的极限平衡分析方法来探讨土工织物的加固作用[2]。然而,在分析时却不能很好地反映土工织物与路堤土之间的变形协调关系     

堆载预压和真空堆载联合预压的比较

堆载预压和真空联合堆载预压都是工程中处理软土地基的常用方法。通过舟山富通电缆项目地基处理工程项目中堆载预压和真空联合堆载预压施工的比较研究,得出真空联合堆载预压比堆载预压具有更高的施工成效效率,更好的沉降稳定性和沉降性,以及水平位移量更小,使周围软弱边界的变形处于较为稳定的状态。     

塑料排水板加固地基固结沉降特性研究

对采用塑料排水板加固软土地基的工程实例进行计算,比较了采用不同排水板间距、不同堆载预压时间、不同堆载高度时地基土层的总沉降、固结度、残余沉降情况,分析了不同地基加固参数对固结度和残余沉降的影响程度,并对地基加固参数的合理选取给出了建议。     

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。     

DIC assessment of foundation soil response for different reinforcement between base and soft subgrade layer – Physical modeling

This paper presents insights from small-scale model tests on statically loaded strip footing on dense base sand supported by a single reinforcement layer. The selected reinforcement includes various lengths of wire mesh and a non-woven geotextile placed on soft subgrade sand. The influence of these inclusions on base and subgrade response (deformations and failure mechanism) is evaluated from the displacement pattern obtained by the digital image correlation (DIC) technique. The benefits of the reinforcement and geotextile were assessed by comparing the results obtained for the improved and unreinforced soil model. Additionally, the confining effect of the reinforcement was experimentally analyzed by comparing the sand displacements around the wire mesh reinforcement with different aperture geometry and geotextile without apertures. These systematically selected reinforcement geometries enabled the investigation of the aperture size influence on base and subgrade behavior during surcharge loading. Results confirm the contribution of reinforcement inclusions to the improved behavior of base and subgrade layers compared to the unreinforced soil. The test results with different reinforcement confirm the influence of the aperture geometry on the model response during the surcharge load application. Compared to large apertures, enhanced confining and membrane actions were obtained for reinforcement with relatively small apertures.     

考虑地基土非线性固结的桩侧负摩阻力计算方法研究

针对软土地基因固结沉降在桩侧引发的负摩阻力问题,从桩土相互作用机理出发,首先,根据软土压缩曲线性质,采用双曲线应力应变模型考虑地基土固结非线性特性,推导了桩侧土沉降随深度和时间变化的计算公式;其次,引入Gibson地基理论考虑地基土的非均质性,结合桩土界面剪应力–剪应变双曲线模型,建立了反映桩土界面剪切刚度系数随深度非线性增长的荷载传递函数。在此基础上,联立桩体平衡方程,获得了桩侧摩阻力、桩身轴力分布和中性点位置。最后,将理论计算曲线与工程实测曲线进行对比,并进一步分析了压缩试验参数、固结度、桩径及桩长、地表堆载对桩侧负摩阻力及中性点位置的影响,结果表明计算方法是可行的,可为类似工程提供参考。     

软土地基综合处治在沿海高速公路中的应用

结合工程概况,介绍了砂垫层 土工格栅 塑料排水板 粉煤灰路堤 超载预压综合处治的设计标准及作用机理,并对处治效果进行了分析,以达到减小地基工后沉降和提高地基承载力的目的。     

土工网在处理吹填粉细砂软基中的应用

本文着重研究Ｎｅｔｌｏｎ土工网处理大面积吹填粉细砂土时的地基承载能力、变形特性、密实度变化情况，并将其与强夯后的地基承载能力进行比较，认为用Ｎｅｔｌｏｎ土工网结构处理吹填粉细砂软基是可行的，并对Ｎｅｔｌｏｎ土工网结构处理吹填粉细砂软基的设计理论进行了初步探讨。     

真空联合堆载预压法处理软土地基

主要探讨了真空联合堆载预压法在高速公路软土地基处理中的应用,简要说明了真空联合堆载预压法的基本概念及其加固机理,并介绍了真空联合堆载预压的设计、施工工艺及检测。     

超载预压条件下公路软基沉降速率的控制标准

针对采用超载预压处理方法卸载后,地基沉降速率会发生变化,其控制标准也有所不同的这种状况,对公路软土地基超载预压的机理和沉降速率的控制标准进行了探讨,并结合具体工程实例,分析了超载预压条件下提前卸载的可行性,以期指导实践。     

软弱滩涂上堤基细砂垫层的适用性研究

 结合浙江省平湖市白沙湾—水口围涂一期工程实例及相应原位监测成果,从堤坝工程对砂垫层的渗透性能需求着手,探讨土工织物加筋和细砂垫层应用于软弱滩涂海堤工程的可行性。数值分析结果表明,基于对固结、变形和稳定的综合考虑,在实际选择砂源时,作为水平排水体的砂垫层渗透系数最好大于5×10－3 cm/s;土工加筋对堤基的沉降和孔压影响不大,对提高堤基的整体稳定性作用显著。当细砂垫层由于渗透系数不满足稳定要求时可采用土工织物加筋。实践结果表明,对于场地附近区域缺乏碎石料而砂源充足的软弱滩涂上的堤防工程,采用细砂作为水平排水垫层兼以土工织物加筋是可行的,所得结论和规律可为类似工程提供理论支持,并指导设计和施工。     

真空堆载联合预压加固沿海滩涂软基的效果分析

结合工程实例,对采用真空堆载联合预压法处理大面积沿海滩涂软基的加固效果进行分析和评价。通过表层沉降监测、孔隙水压力监测以及地基施工完成后的十字板剪切试验和浅层平板载荷检测等,得出处理后的软土层沉降量接近1．5m、软土地基物理力学性质变化明显、地基承载力得到大幅提高,表明采用真空堆载联合预压法处理沿海滩涂软基是可行的,具有良好的推广前景。     

A case study of geotextile-reinforced embankment on soft ground

Full-scale test embankments, with and without geotextile reinforcement, were constructed on soft Bangkok clay. The performances of these embankments are evaluated and compared with each other on the basis of field measurements and FEM analysis. The analyses of failure mechanisms and the investigations on the embankment stability using undrained conditions were also done to determine the critical embankment height and the corresponding geotextile strain. The high-strength geotextile can reduce the plastic deformation in the underlying foundation soil, increase the collapse height of the embankment on soft ground, and produce a two-step failure mechanism. In this case study, the critical strain in the geotextile corresponding to the primary failure of foundation soils may be taken as 2.5–3% irrespective of the geotextile reinforcement stiffness.     

CAD on geocomposite vertical strip drains

In recent years, an increasing need has arisen for various types of construction on sites underlain by soft cohesive soils. In such cases, some methods of soil improvement are usually required to provide adequate bearing capacity and tolerable postconstruction total and differential settlements. These goals often may be achieved by precompression or preloading the site prior to construction. Precompression and preloading are frequently used in combination with vertical drains, especially in very thick soft deposits, otherwise the time required for consolidation may be unacceptably long or the instability of the foundation may be a serious concern. Therefore, the vertical geocomposite (jute and coir) drain may be used to accelerate the settlement of soil thereby making the site available for use in the shortest time. The computer program and the design chart for determining the spacing between geocomposite drains are presented. This technique is generally useful for embankment construction, tank foundation, underwater construction and landfill areas. Two projects (Haldia in West Bengal and Vashi Station Complex in Bombay) have utilized the application of geocomposite drains reported in this paper.     

上海虹桥机场塑料板排水固结法软土地基处理技术

结合上海虹桥机场扩建工程软土地基处理,分析塑料板排水固结法的可行性,系统研究了其在软土地基中的应用方法.通过对比计算论证了塑料板排水同结法在该地区的优势,并指出砂垫层铺设、塑料排水板施工、土方回填等施工技术措施.监测结果表明,塑料板排水固结法明显地改善了软土层的排水固结过程,技术可靠,经济合理,能够缩短工期,可以在软土地区推广.