土钉墙技术在边坡支护中的应用

采用土钉墙技术进行深基坑支护能充分利用材料的性能及土体与直的共同作用形成土钉休复合结构，使挡土结构经济合理，施工方便，是一种较理想的挡土结构。     

土钉支护设计与施工

在城市地区进行深基坑开挖支护是土木工程中最为复杂的技术领域之一,它不仅要保证基坑施工过程中的土体稳定,而且要严格限制周边的地层位移以确保环境安全.土钉墙支护是近年发展起来用于土体开挖和边坡稳定的一种新的挡土技术,由于土钉支护具有施工速度快、用料省、造价低的优点,故其已在深基坑支护中得到了广泛的应用.以下以兰州石油化工公司3#公寓楼工程为例讲这种支护模式的设计和施工情况.     

土钉支护及其应用

土钉支护是一种用于土体开挖和边坡稳定的新型支挡结构，具有良好的延性破坏特征。通过土钉支护在济钢中厚板厂二期工程中的应用实例，介绍了土钉支护的局部和整体稳定性计算及工程设计方法，并指出土钉支护应注意的问题。     

预应力锚杆复合土钉墙支护技术在宣钢深基坑中的应用

介绍了对施工场地狭窄、周围紧邻已有建筑物的深基坑,采用预应力锚杆复合土钉墙支护技术进行施工的情况。通过基坑支护设计、方案比较及理论验算,并在施工环节采取一些有效措施,克服了施工的难点,使预应力锚杆复合土钉墙这一支护技术在深基坑工程中得以较好应用。该施工技术缩短了工期,节约了大量资金,成功地解决了基坑边坡的强度及稳定性问题,保证了安全施工。     

深基坑土钉支护数值模拟

基于FLAC3D的基本原理及其求解过程，对深基坑工程土钉墙支护做了数值模拟，对不同土钉长度、倾角的4种支护方案进行了对比选择。对所选支护方案的计算结果进行分析，得出一些有用的结论，对深基坑土钉墙支护设计及合理施工有一定的指导意义。     

韶钢3号高炉改造基坑支护技术

介绍韶钢3号高炉改造新建渣池工程基坑支护结构的选择原则及由槽钢排桩、钢丝绳锚拉与钢管支撑组成的综合基坑支护体系的设计要点、实施过程、技术措施及施工监测过程；同时提出了用经改造的小型钻机打钢板桩的新方法．施工监测数据表明，该技术与常规的钢筋混凝土板桩，土钉或喷锚、围幕或地下连续墙等支护技术方法至少节省了45万元以上的投资，建设工期提前了40多d．     

土钉墙支护技术综述

近年来，土钉技术在深基坑和边坡稳定中的应用日益广泛。本文对土钉墙支护的特点、国内外的研究状况以及设计中应注意的问题进行了详细的阐述。     

土钉支护技术在某饭店深基坑中的应用

某饭店工程深基坑采用土钉支护，通过设计、施工、监测多环节的控制，并从现场量测数据分析表明：基坑最大水平位移发生在基坑顶部；雨季随着雨水渗入土体基坑水平位移增长发生较大变化；施工中通过现场监控，及时对原设计作出必要的修改和采取必要的措施，确保了基坑的安全。     

土钉支护技术在软土基坑开挖中的应用

某花园商住大厦地基土层为软土,基坑开挖时,采用土钉支护技术进行设计与施工,确保了基坑土体的整体稳定,避免了基坑开挖对周边环境的不利影响.     

基坑复合的土钉支护

概述了利用复合土钉支护技术处理工程基坑支护的结构设计及施工工艺，并提出这种技术处理与周边基础及市政管线问题中所应采取的措施及效果。     

Influence of Overburden Pressure on Soil–Nail Pullout Resistance in a Compacted Fill

Soil nailing has been widely used in many places in the world in the last two decades because of its technical and economical advantages. The nail–soil interface shear strength is an important parameter in soil nail design. This parameter is governed by a number of factors, among which the influence of the overburden pressure (or soil depth) is the most controversial. There are differing views concerning the effect of overburden on the nail–soil interface shear strength. In order to examine the influence of the overburden pressure, a series of laboratory pullout tests on soil nails installed in compacted completely decomposed granite fill have been conducted using two pullout boxes. Numerical simulations have also been carried out and the results are compared with the pullout test data. The procedures of the pullout tests and new features of the pullout boxes used are briefly described. Changes of the vertical stress in soil close to the nail throughout the course of soil nail installation and pullout are presented and discussed in detail. It is observed from the results of this study that the installation process of soil nail induced significant vertical stress changes in soil around the soil nails, and that the soil nail pullout shear resistance is independent of the overburden pressure (or soil depth).     

Field Pullout Testing and Performance Evaluation of GFRP Soil Nails

Glass fiber–reinforced polymer (GFRP) materials provide practical solutions to corrosion and site-maneuvering problems for civil infrastructures using conventional steel bars as reinforcements. In this study, the feasibility of using GFRP soil nails for slope stabilization is evaluated. The GFRP soil nail system consists of a GFRP pipe installed by the double-grouting technique. Two field-scale pullout tests were performed at a slope site. Fiber Bragg grating (FBG) sensors, strain gauges, linear variable displacement transformers (LVDTs), and a load cell were used to measure axial strain distributions and pullout force-displacement relationships during testing. The pullout test results of steel soil nails at another slope site are also presented for comparison. It is proven that the load transfer mechanisms of GFRP and steel soil nails have certain difference. Based on these test results, a simplified model using a hyperbolic shear stress-strain relationship was developed to describe the pullout performance of the GFRP soil nail. A parametric study was conducted using this model to study some factors affecting the pullout behavior of GFRP soil nails, including nail diameter, shear resistance of soil-grout interface, and ratio of interface shear coefficient to the Young’s modulus of the nail. The results indicate that the GFRP soil nail may exhibit excessive pullout displacement and thus a lower allowable pullout resistance than with the steel soil nail.     

浅谈岩土工程深基坑支护的设计与施工

社会的发展进步不断推动着基础建设领域的迅猛发展。高层建筑以其占地少,利用空间大,现代化气息强的优点逐渐受到各大城市的青睐。高层建筑对深基坑支护的设计施工提出了更高的要求。本文对岩土工程深基坑支护设计、具体支护设计与支护施工环节中出现的各种问题以及相关的解决策略进行重点论述研究。     

基于Q系统的某铜矿巷道分级支护技术及工程应用

合理的支护方式是控制巷道稳定和变形的重要手段之一,而工程岩体质量评价是确定合理支护方案的重要依据.针对某铜矿存在的支护方式单一、支护效率低、支护成本较高的问题,采用Q系统和RMR法对该矿山4个工程岩组进行了岩体质量分级.基于Q系统支护图,并结合矿山支护工艺、施工条件等因素,制定和优化了分级支护方案及支护参数;利用RMR...     

Rapid Pullout Test of Soil Nail

This technical paper describes the rapid pullout response of soil nail embedded in dry clean sand. In the rapid pullout test, soil nail is pullout by a tensile impulse load with loading duration that is long enough to eliminate the influence of the stress wave propagation phenomenon. The results of these experiments showed the influence of loading rate on pullout response is highly dependent on the roughness condition of the nail surface. For rough nail, the prepeak rapid pullout response was significantly stiffer in the load-displacement characteristic and higher in peak pullout strength when compared to the corresponding quasi-static pullout response. While for a smooth nail, a negligible difference between rapid and quasi-static pullout response was noticed. In light of these limited experimental results, the radiation damping effect appears to be the dominant contributor to the enhancements in prepeak rapid pullout response of rough nail. “Actual” damping coefficient that quantifies the damping resistance mobilized in a rapid pullout test was found not to be constant but to decrease with the increase in pullout displacement.     

Decision Support System for Microtunneling Applications

Microtunneling is a trenchless technology method used for installing new pipelines. The inherent advantages of this method over open-cut trenching have led to its increasing use since its first introduction into North America in the early 1980s. With this technology, surface disruption can be minimized, especially in urban areas, and high accuracy of installation (usually less than 2?cm over 100?m) can be achieved in both line and grade. But microtunneling machines are very expensive and few contractors have extensive experience with this technology. Microtunneling can also be risky when unexpected obstacles or soil changes occur. Careful constructability analysis is needed, and an appropriate microtunneling method should be selected in order to achieve successful completion of microtunneling projects. A computerized decision support system (DSS) for microtunneling was developed to support decision making for contractors who want to bid on microtunneling projects. This paper discusses the decision-making process for microtunneling and the development of the DSS. When the user enters basic information about the potential project such as drive length, installation depth, pipe diameter, and soil condition, the DSS evaluates whether microtunneling will be economically feasible and suggests appropriate types of microtunneling methods. The user can then select microtunneling machines, types of pipes, and types of shaft construction methods. This DSS is most beneficial when used at the preplanning stage by utility contractors.     

斜井锁口段快速施工与高效支护技术研究

斜井是直通地面的倾斜坑道,是重要的地下工程之一。由于斜井洞口段埋深浅,表层风化严重、岩体破碎,此段施工易造成地面塌陷,施工难度大,特别是由锁口段与基岩的过渡段,其施工工艺与支护技术成为影响斜井洞口段的难题。为确保斜井在过渡段的安全施工,需通过超前支护、人工开挖、锁口段加强支护及锁口段到基岩段联合支护的系统措施,该措施可解决工艺复杂、成本高的问题,有着施工工艺简单、快速支护、安全高效等特点。     

有色金属锚杆支护的关键理论教学研究

在有色金属开采的作业中,支护是保证施工人员安全生产的基石,其重要程度不言而喻,当下金属开采作业中常采用的支护方法有:支架型支护、砌筑型支护、锚杆性支护,生产作业时并不会单一使用支护类型,而是组合型使用不同的支护方法,在此本文不与赘述。本文将就我国有色金属矿山运用最多的锚杆支护做一个详细的研究分析,为教学研究提供一些实践以及理论知识支撑。     

程潮铁矿截排洪隧洞支护优化研究

结合武钢程潮铁矿矿区截排洪续建工程,运用岩土数值分析软件对各类围岩条件下隧洞开挖及支护结构进行数值模拟。并确定隧洞合理的开挖与最优的支护方案。在保证隧洞安全的前提条件下,合理地进行支护设计与施工,尽量节约工程造价和工程投资,保证截排洪工程尽早完成。     

关于岩土工程基础施工中深基坑支护施工技术的相关分析

我国现代化建设的步伐逐渐加快,为拉动国民经济水平提升奠定了基础,同时也满足了社会生产生活的实际需求。岩土工程基础施工工作,会对整个工程项目的质量产生直接影响,因此受到人们的高度重视。尤其是深基坑支护施工,是基础施工的主要内容,应该保障施工质量与安全性,防止给人们的生命财产带来严重损失。因此,应该对深基坑支护施工的技术要点进行控制,满足工程的整体规划要求。本文将通过介绍岩土工程基础施工中深基坑支护施工技术的特点,结合实例分析其应用方法。