粉喷桩加土工格栅复合地基处理施工技术浅析

本文介绍了粉喷桩加土工格栅复合地基加固机理 ,提出了粉喷桩加土工格栅的施工方法及施工中常见问题的解决办法。     

如何减少软弱地基上建筑物的不均匀沉降

软弱地基上建筑物的不均匀沉降 ,常导致建筑物的开裂、破坏 ,严重地影响使用。本文主要从地基处理、建筑、结构、施工等方面对如何减少软弱地基上建筑物的不均匀沉降进行了论述。     

垫层法处理软弱地基的设计及其适用范围

介绍垫层法处理软弱地基的适用范围、设计、施工、验收以及工程实例。     

柳钢棒线厂2号加热炉基础施工

主要论述了柳钢棒线厂2号加热炉基础施工中的边坡支护方法，软弱地基处理方案的选择、确定以及通过化学注浆方法提高地基承载力的实践经验。     

粉喷桩复合地基的设计与应用探讨

本文介绍了粉喷桩复合地基设计计算的基本方法，施工中的一些问题进行了分析和探讨，结合一个工程实例，介绍了粉喷桩复合地基的设计过程，并对设计与测试结果作了对比分析。     

砂石垫层设计和施工中的质量控制

砂石垫层的作用是:提高浅基础下地基承载力、减少沉降量、加速软弱土层的排水固结等。正由于砂石垫层诸多作用,当建筑物基础下的持力层比较软弱,不能满足上部荷载对地基的要求时,常采用砂石垫层来处理软弱土地基。本文仅对砂石垫层设计施工质量控制提出几点看法。 1 影响石垫层设计质量的因素 1.1 砂石垫层厚度(z)与基础底面宽度、长度的关系。 一般的基础底面长度、宽度及砂石垫层厚度z的确定,既要考虑砂石垫层地基承载     

浅述夯扩灰渣土桩地基处理

采用由拆房土组成的碎石三合土为桩体材料的夯扩灰渣土桩进行软弱地基的地基处理,与同类型工程相比,不仅极大地降低工程费用,而且技术可行、施工简便。更主要地是能消耗掉大量的建筑垃圾,对城市环境保护起到了一定的作用。     

夯实水泥土桩在复合地基中的应用

本文介绍了采用夯实水泥土桩在实际工程中处理软弱、湿陷性地基的施工方法和适用条件。     

水泥粉喷桩复合地基的研究综述

水泥粉喷桩作为一种加固地基的有效方法 ,可以较大地提高地基承载力 ,改善地基的变形特性 ,减小在荷载作用下可能发生的沉降和不均匀沉降。从水泥土的工程性质、复合地基承载力的计算以及复合地基的沉降计算几个方面分析了水泥粉喷桩的研究现状 ,并对以后研究的方向提出了见解     

钻孔灌注桩加固柱基础在二轧成品库栈桥柱纠偏大修中的可行性探讨

结合工程实际情况认为采用钻孔灌柱桩的施工方法,可以解决在软弱地基土层上加固柱基础的难题,以及施工与正常生产的矛盾。     

软土地基处理方案的技术经济分析

结合井睦高速公路工程项目中的山涧淤泥质土-砂混合软土地基,通过采用松木桩、CFG桩和水泥深层搅拌桩对该软基进行处理,并对这3种软基处理方案进行技术比较与经济分析,以便得到最优处理方案.研究表明:松木桩的造价在3种处理方式中是最高的,而且松木桩受处理深度和承载力的限制,它不是最佳的选择方案;在相同的条件下,CFG桩法处理地基的造价是水泥深层搅拌法处理地基的1.4倍左右,造价较为昂贵;最终确定选用水泥深层搅拌桩法加固该工程的淤泥质土-砂混合软土地基.     

旋喷桩在烟囱基础工程中的应用

旋喷桩一般仅用于补强加固，在韶钢3号高炉原地大修改造工程中把旋喷桩作为60m烟囟基础的持力桩进行应用，桩基设计参照桩基工程规程、规范，现场地质条件、旋喷桩体的主要特征和力学特征，结合多年的施工经验，旋喷桩施工中采用单管旋喷注浆技术，最大喷射压力达到20MPa，同时在浆液中加入外加剂，并采取有效防止孔内串浆和漏浆等一系列技术措施，以保证单桩承载力达到700kN以上，有效直径达到700mm以上，经检验，完成后的桩体满足设计要求，从而表明旋喷桩可以作为持力桩加以开发应用。     

水泥深层搅拌地基加固原理及实例

结合工程实例对水泥深层搅拌地基处理原理、适用范围进行了探讨，并详细介绍了水泥深层搅拌桩的计算方法，为软弱土地基处理提供了可靠、经济的途径。     

深层搅拌桩在软土地基的应用

以建在软土地基上的商住楼采用深层搅拌桩为实例,对该施工工艺加固地基时在设计、施工方面的一些问题作了分析、研究,揭示了由复合地基载荷试验获得的复合地基承载力标准值和通过理论公式计算的复合地基承载力标准值的关系.     

预应力混凝土管桩的施工技术

预应力混凝土管桩具有单桩承载力高，桩身耐击性好，穿透力强和造价便宜等优点，在基础工程中得到广泛的应用，根据工程实践，针对预应力混凝土管桩的施工特点，阐述了测量放线、管桩的堆放与验收、施工机械的配备、施工流水安排及施工工艺流程，管桩的焊接做法，打桩控制等方面的关键技术及措施。     

Pile Construction Productivity Assessment

Bored piles are vital elements for highway bridge foundation. A large number of factors oversees productivity and cost estimation processes for piles, which creates many problems for the time and cost estimators of such process. Therefore, current study is designed to diagnose these problems and assess productivity, cycle time, and cost for pile construction using the artificial neural network (ANN). Data were collected for this study through designated questionnaires, site interviews, and telephone calls to experts in different construction companies. Many variables have been considered to manage the piling construction process. Three-layer, feed forward, and fully connected ANNs were trained with an architecture of seven input neurons, five output neurons, and different hidden layer neurons. The ANN models were validated and proved their robustness in output assessments. Three sets of charts have been developed to assess productivity, cycle time, and cost. This research is relevant to both industry practitioners and researchers. It provides sets of charts for practitioners’ usage to schedule and price out pile construction projects. In addition, it provides researchers with a methodology of applying ANN to pile construction process, its limitation, and future suggestions.     

A Robust Macroelement Model for Soil–Pile Interaction under Cyclic Loads

The principal focus of this study is the development of a robust macroelement model for soil–pile interaction under cyclic loads. The model incorporates frictional forces and formation of gaps at the soil–pile interface as well as hysteretic behavior of the soil. The plastic envelope of the soil behavior is modeled via the so-called p–y approach, outlined in American Petroleum Institute’s guidelines for design of foundation piles for offshore platforms. The macroelement is an intuitive assembly of various basic elements, each of which incorporating a particular aspect of the soil–pile interaction. The modular structure of this macroelement allows straightforward adaptation of improved constitutive models for its building blocks. Herein, we focus on large-diameter, cast-in-drilled-hole reinforced concrete piles (piers) that are partially or fully embedded in soil. These types of piles are frequently used as support structures in highway construction. Consequently, the numerical robustness of the interaction model is assessed with parametric studies on pile systems and soil types relevant to this type of construction. Both elastic and inelastic pile behaviors are considered in the parametric studies. The results indicate that the proposed interaction element is numerically robust, and thus, amenable to routine structural analysis.     

Performance of a Geogrid-Reinforced and Pile-Supported Highway Embankment over Soft Clay: Case Study

This paper describes a case history of a geogrid-reinforced and pile-supported (GRPS) highway embankment with a low area improvement ratio of 8.7%. Field monitored data from contact pressures acting on the pile and soil surfaces, pore-water pressures, settlements and lateral displacements are reported and discussed. The case history is backanalyzed by carrying out three-dimensional (3D) fully coupled finite-element analysis. The measured and computed results are compared and discussed. Based on the field observations of contact stresses and pore-water pressures and the numerical simulations of the embankment construction, it is clear that there was a significant load transfer from the soil to the piles due to soil arching. The measured contact pressure acting on the pile was about 14 times higher than that acting on the soil located between the piles. This transfer greatly reduced excess positive pore water pressures induced in the soft silty clay. The measured excess pore water pressure ratio max in the soft silty clay was only about 0.3. For embankment higher than 2.5?m, predictions of stress reduction ratio based on two common existing design methods are consistent with the measured values and the 3D numerical simulations. During the construction of the piled embankment, the measured lateral displacement–settlement ratio was only about 0.2. This suggests that the use of GRPS system can reduce lateral displacements and enhance the stability of an embankment significantly.     

深层水泥土搅拌桩施工质量监理要点

通过工程实践，从监理的角度对深层搅拌桩的施工阶段质量监控要点进行阐述。     

深层搅拌桩在软基加固中的应用

深层搅拌法是以水泥作固化剂，通过专用的深层搅拌机械，在地基深部就地将土和水泥搅拌而成加固体，应用该法处理地基可增加地基承载力，减小沉降。文章结合工程实例，简述了深层搅拌法处理软土地基的设计步骤。