确保深层搅拌桩在基坑支挡中施工质量的措施

从深层搅拌桩的施工顺序，施工前准备工作，喷浆次数与成桩质量的关系，补桩方法，施工中应注意的问题等几方面介绍了如何确保深层搅拌桩在基坑支挡中的施工质量。     

深层搅拌桩加固软土地基的应用研究

深层搅拌桩广泛用于软基加固工程。当软土含水率＞50％时，可采用喷粉施工；反之，宜采用喷浆施工工艺，水泥土的加固，可用调节搅拌轴回转速度来控制搅拌效果。根据某镇工程实例的工程地质条件，介绍了具体的施工工序，指出严格执行操作规程和确保水泥质量，是保证加固桩体强度与均匀性的关键。施工中必须合理选择施工工艺和实行质量控制，以避免断桩或搅拌不均匀，生产实践表明，深层搅拌桩加固软基工艺成桩快、成本低，有利于环境保护。     

钢板桩在东建大厦地下室基坑支护工程中应用

以东建大厦地下室基坑支护施工为例，介绍了新引进的钢板桩基坑支护工程施工工艺，即在基坑内采用一层内撑式钢板桩围护体系，应用SMW工法（钢板桩外侧加搅拌桩），钢板桩用H型钢，周边搅拌桩采用水泥土搅拌桩。搅拌桩采用“二次喷浆、二次搅拌”工艺，并制定了施工流程及相应的技术措施，     

江苏高速公路水泥搅拌桩检测有关问题探讨

通过对江苏高速公路水泥搅拌桩检测方法依据、检测内容及评分标准的介绍，着重对水泥搅拌桩检测中发现的问题如标贯击数偏低、断桩和桩长不够等进行了分析，并对如何提高水泥搅拌桩的施工质量提出了建议。     

钉形水泥土双向搅拌桩加固软土地基的效果分析

针对水泥土搅拌桩应用中存在的问题,介绍了最新研制的钉形水泥土双向搅拌桩及其施工工艺。施工质量检验表明,钉形水泥土双向搅拌桩桩体质量好于常规水泥土搅拌桩,钉形水泥土双向搅拌桩单桩及复合地基承载力分别较常规水泥土搅拌桩的单桩及复合地基承载力有较大提高。通过对试验段的观测成果分析,论证了钉形水泥土双向搅拌桩加固软土地基优越的工程特性。     

SJC型水泥土搅拌桩浆量监测记录仪的应用

采用SJC型流量仪监测系统来控制深层搅拌桩施工质量，对成桩过程中掌握注浆量的分布、控制桩顶、桩底标高以及确保施工桩长、杜绝断浆现象提供了施工数据，而且也为检验、验收部门提供反映搅拌桩质量的第一手资料，为判断成桩质量提供了最直接的依据。     

水泥土搅拌桩桩身质量的电阻率分析

通过对某高速公路软基处理试验段水泥土搅拌桩芯样强度与电阻率指标的分析发现,水泥土搅拌桩的桩身质量与其施工工艺密切相关;在特定的施工工艺条件下,水泥掺入比与搅拌均匀性是影响桩身质量的2个重要因素;在相同深度处,桩身水泥土芯样的竖向电阻率高于其水平向电阻率;桩身水泥土芯样的电阻率与其无侧限抗压强度之间存在着很好的线性相关关系;水泥体芯样水平向电阻率的标准差在一定程度上反映了水泥掺入量和搅拌均匀性。综上所述,利用水泥土的电阻率及其相关指标对大规模施工条件下水泥土搅拌桩的桩身质量进行定量分析是一种经济、无损、简便和科学的方法。     

水泥土搅拌桩在卵砾石地层的应用研究进展

卵砾石地层可压缩性低、抗剪强度大,水泥土搅拌桩工法在应用于卵砾石地层时存在若干技术问题。系统总结了水泥土搅拌桩工法在卵砾石地层的应用情况,重点对水泥土搅拌桩应用于卵砾石地层的技术难点及主要的改进措施进行了论述,并分析了各改进方法的作用机理、适用性、利弊等。水泥土搅拌桩在穿越卵砾石地层过程中存在施工效率低下、钻具磨损大、施工质量不易控制等技术难题,目前已有水泥土搅拌桩应用于卵砾石地层的成功案例中主要改进工艺可分为钻进、搅拌、排渣共计三大类别,具体可细化为提高动力机头功率、控制钻头钻压及转速、提高钻具材料强度、改进钻头及搅拌叶片结构形式、使用土体改良剂等措施,必要时可引入引孔换填、冲击破碎等工法辅助施工。但总体上应用成功的案例中,卵砾石地层的颗粒粒径及厚度较小,一般粒径不超过150 mm,且未形成系统性的卵砾石地层特征与机械设备技术参数的匹配方法。搅拌桩设备与卵砾石地层相互作用机理研究等工作亟待深化。     

水泥深层搅拌桩在软基加固处理中的设计与施工

通过具体工程实例，介绍了水泥深层搅拌桩在软基处理设计中如何有效地选用设计参数和利用岩土勘察资料进行设计；阐述了施工中主要施工工艺流程以及有效控制水泥深层搅拌桩成桩质量的措施。     

对“搅拌桩”的几点认识

搅拌桩设计及施工已列入规范，在使用中有成功的例子，也有失败的教训。本文从水泥土搅拌桩的基本特点、适用性、影响搅拌桩成桩质量的主要因素及如何提高搅拌桩的均匀性四方面谈了对水泥土搅拌桩的认识。     

双向水泥土搅拌桩加固软土地基试验研究

针对国内水泥土搅拌桩应用中存在的技术问题,介绍了自行研制的双向水泥土搅拌桩及其施工工艺;通过工程实例和试验数据分析,对双向水泥土搅拌桩与常规水泥土搅拌桩在现场施工工艺、标准贯入试验、桩身芯样无侧限抗压强度和电阻率试验以及经济、社会效益等方面进行了对比分析。研究表明,双向水泥土搅拌桩具有优越的工程特性及较大的社会经济效益。     

The Deep Mixing Method: Bearing Capacity Studies

Nowadays, several techniques are employed to improve the problem of carrying out construction in soft soils by increasing the strength of the soil foundation and reducing the settlement of the soil. Among these stabilizing techniques, the deep mixing method is regarded as the most popular. The deep mixing method is a soil modification method where the soil is mixed in situ with stabilizing agents, commonly soil–cement columns. It increases the strength of the soil, providing bearing resistance and improved settlement performance. Deep mixing is carried out in situ using a machine equipped with mixing blades mounted at the end of a tube that has a nozzle at the lower end. The stabilizer agent is injected into the soil via the nozzle using a pumping system so that it mixes with the soil as the blades are rotated. Throughout this paper, previous works by numerous researchers on deep mixing including laboratory work, full-scale field tests, analytical and numerical analyses related to bearing capacity are reviewed. The techniques and results used are discussed with the help of figures depicting charts, failure modes, and the model configuration setup. It was found that the deep mixing method is suitable for use with any type of soil and provides a better alternative to the existing method of improving soft clay ground, especially with regard to the soil bearing capacity. In addition, future research is needed to improve the use of the method for soil improvement in the construction industry.     

水泥土搅拌桩在高层建筑地基处理中的应用

结合工程实例,介绍了水泥土搅拌桩在高层建筑地基处理中的设计计算、施工质量控制和检测方法与结果。检测结果证明,水泥土搅拌桩应用于高层建筑的地基处理是可靠和可行的。     

二灰改良土动力特性试验研究

近10多年来,二灰改良土以其造价低、有利于环保、后期强度高等特点,已普遍用做路面的底基层和基层。通过对素土和不同比例的二灰土改良土进行动强度,动弹模试验,研究二灰含量对动力参数的影响,并列出了几种配比的试验结果供比较和参考。试验结果表明,二灰含量不宜大于40%,否则意义不大,且不经济。     

三轴水泥土搅拌加固地基的应用与控制

文章阐述了三轴深层水泥土搅拌加固桩在浦东机场地道工程中的应用情况,并针对深层水泥土搅拌桩各个施工环节,提出了相应的质量控制措施.     

空间数据仓库元数据的结构体系

给出了空间数据仓库元数据的基本概念，说明了空间数据仓库元数据的相关技术．重点论述了空间数据仓库元数据的结构体系是由11类信息组成，它们分别是空间数据标识信息、区域范围信息、邻接信息、表示信息、数学基础信息、数据集内容信息、质量信息、分发信息、安全信息、联系信息和时间信息，并设计出了空间数据仓库元数据的组织结构。     

Numerical analysis of lateral movements and strut forces in deep cement mixing walls with top-down construction in soft clay

This article presents the observed and simulated lateral movements and strut forces induced in deep cement mixing walls under deep excavation using top-down construction techniques in soft Bangkok clay. The walls are supported laterally by permanent concrete slabs and temporary struts. A three-dimensional numerical model is first calibrated with observed data from a case study. Then, a parametric study is performed to compare this construction method with the bottom-up method and investigate the influence of the DCM wall thickness on lateral movements and strut forces of the wall.     

Effectiveness of deep cement mixing walls with top-down construction for deep excavations in soft clay: case study and 3D simulation

This paper presents the observed and simulated effectiveness of deep cement mixing walls created using top-down (DCM-TD) construction techniques for a deep excavation in soft Bangkok clay. The wall system consisted of four rows of 0.7-m-diameter DCM columns, and the bracing system consisted of two 0.25-m-thick basement slabs and seven temporary struts. The effectiveness of the wall system compared to that of other wall systems was evaluated using the measured results of previous case studies. A 3D numerical analysis was performed to calculate forces in the basement slabs and bending moments in the DCM wall. Finally, series of parametric analyses of both DCM-TD and deep cement mixing walls created using bottom-up (DCM-BU) construction techniques were carried out, and their results were compared to highlight the effectiveness of DCM-TD and its applicability to excavations at greater depths. The field and numerical results show that DCM-TD is more effective than DCM-BU in terms of the limitations of lateral wall movement, the bending moment in a DCM wall and the thickness of a DCM wall for various depths because of a larger system stiffness. Therefore, DCM-TD is very effective and suitable for use in potential future deep excavations in urban areas.