汉宜高速公路荆沙段路面纵向裂缝治理方案研究

论述了路面纵缝开裂的形成机制,高路堤路段内因是边坡坡度过陡,填土具有一定的胀缩性,外因是雨水入侵,低路堤路段是由于存在切过地基的滑动面,缓慢蠕滑所致。探讨了治理方案,前者可采用喷锚或高压旋喷注浆＋高压注浆方案,后者可采用挡土墙或砌石＋高压注浆或抗滑桩＋高压注浆方案治理。     

延安银海大厦基坑软弱土层的支护处理

分析了延安银海高科技大厦深基坑区工程地质水文地质条件,根据基坑施工中遇见的具体情况,优选了旋喷桩与土钉墙构筑复合重力式挡土墙的方案进行施工,避免了水土流失,减少了基坑变形,支护稳定,效果良好。      

GX-1型多功能旋喷钻机及配套钻具

简介了GX-1型多功能旋喷钻机及配套钻具的结构特点和生产试验情况。结果表明,该钻机性能可靠,结构合理,适合于多种地层的成孔与旋喷施工工艺。      

高压旋喷注浆在桥梁地基加固中的应用

国道108线K9＋694．10沙河立交小桥地基采用高压旋喷注浆法加固。系统介绍了工程概况、设计方案、注浆施工，并通过现场试验证明了高压旋喷注浆法加固桥梁地基是一项成功实践。     

旋喷水泥护壁在湖北放马山矿区ZK10409孔的应用

结合湖北放马山矿区ZK10409孔钻进实例,分析了岩心钻探旋喷水泥护壁原理及特点,介绍了旋喷水泥灌注机具及其在岩心钻探中的具体操作方法,阐述了岩心钻探旋喷护壁水泥的效果。     

应用于污染场地原位修复的旋喷工艺研究

从原位修复需求、旋喷技术特点等方面分析高压旋喷注浆技术在污染场地原位修复中的应用前景。根据污染场地原位修复需要,有针对性地对传统二重管法旋喷工艺参数进行改进设计,以提高旋喷技术在污染场地原位修复中的适用性,并开展现场试验研究以验证参数设计合理性,为后续此类工程推广应用提供技术借鉴。     

旋喷施工基本规程参数综述

本文对旋喷工艺的规程参数进行了综述，整理、描述和解释了旋喷工艺的基本物理过程，简要叙述了几年来各种旋喷工艺方法和它们的发展变化。考虑到旋喷工艺的设计应用，美国土木工程师学会（ＡＳＣＥ）在１９８７年指出旋喷工艺最重要的参数是：喷浆材料、喷嘴能量、喷浆流速、喷浆管的回转速度和提升速度。专业的基础处理公司根据它们的经验和设备条件可采用许多方法调整这些参数来满足工程需要。作者根据有关文献及自己收集的材料在     

运用旋喷注浆法处理断桩事故

运用旋喷注浆法处理断桩事故核工业长沙工程勘察院张龙才１问题的提出断桩是钻孔灌注桩施工中极为严重的质量事故，若在施工中发现断桩则可采用接桩法补救。但很多断桩是在验桩时发现的，此时桩已形成，用接桩法显然弊端诸多，而采用旋喷注浆法则比较理想。２工作原理旋喷...     

放旋喷固结全的物理力学性状研究

通过单轴抗压试验，剪切试验，变形试验及渗透性试验等方法，对旋喷固结体的物理力学性状和渗透性进行了研究。结果表明，旋喷固结体具有良好的物理力学性质和较低的渗透性，呆完全发迹天然土的性质。     

钻孔灌注桩缺陷桩处理实践

在颍河特大桥桩基施工中灌注35号墩-1桩基时，混凝土输送泵出现故障造成浇注中断，桩基检测时发现缺陷，采用旋喷压浆技术进行处理，经检测合格。对采用旋喷压浆处理桩基缺陷的全过程进行了介绍，并对施工中出现的技术问题进行分析。     

高压喷射灌浆在处理构筑缺陷中的应用

本文介绍某热电厂在加固地基缺陷的施工中,采用高压喷射灌浆方法处理的主要技术参数及其效果。     

填海造陆区旋喷桩止水帷幕施工实践

填海造陆区地层回填时间短,填料成分多以开山碎石为主,结构松散,空隙大,地下水与海水连通性好,在潮汐作用下,海水的冲刷能力强,在该类地层中施工止水帷幕存在成孔难和浆液难在原处凝固2个技术难题。在详细地分析了施工区的工程地质条件后对旋喷桩的成孔工艺和施工顺序进行了大胆的尝试和创新,并在施工过程中进行了合理的改进和优化,取得了良好的施工效果。     

超浅覆大断面暗挖隧道下穿富水河道施工风险分析及控制研究

以广－珠铁路江门隧道下穿富水河道段为依托,针对其超浅覆、大断面、富水等特点,对超浅覆大断面暗挖隧道下穿富水河道的风险源进行系统分析,阐述风险产生的原因及造成的危害。在对可能采用的预加固手段及开挖方案进行初步比选后,采用三维数值模拟手段进一步量化比选,提出在地表隔水措施基础上,采用水平旋喷与大管棚复合超前支护并结合三台阶法开挖方案。研究表明,该方案能有效止水并加固地层,有效规避塌方风险,保证隧道施工安全的同时,加快施工进度及降低造价,可为类似工程提供参考。     

基坑开挖对邻近铁路路基变形影响与控制

以某紧邻既有铁路线的基坑工程为依托,基于现场实测数据,分析了路基与基坑的变形规律、沉降原因和控制措施。结果表明,受列车荷载与渗漏水影响,路基沉降在坑底旋喷加固和施工冠梁、混凝土撑期间迅速增加,形成了长约50 m、最大沉降95 mm的沉降槽,60%以上的路基在该阶段的沉降增量占阶段累计沉降的70%以上,而地表沉降多小于20 mm,约为开挖深度的2.4‰;路基沉降槽处坑外横断面地表沉降呈“凹槽形”,在路基处沉降最大。在坡顶进行双液注浆能够控制地表与路基沉降,减少后续开挖施工对路基的影响,但注浆施工易导致边坡变形突变,尤其是向坑内的水平位移,不利于边坡稳定和铁路安全。     

Field testing of one-way and two-way cyclic lateral responses of single and jet-grouting reinforced piles in soft clay

Piles supporting transmission towers, offshore structures (such as wind turbines), or infrastructures in seismic areas are frequently subjected to either one-way or two-way cyclic lateral loadings. Relatively little attention, however, has been paid to compare and understand the effects of different loading regimes (one-way or two-way cycling) on lateral responses of piles in soft clay. For this reason, a series of field tests in soft clay are carried out to compare one-way and two-way cyclic responses of single piles and of jet-grouting reinforced piles. The field tests reveal that the single pile subjected to two-way cycling experiences much more rapid degradation in lateral stiffness and capacity, but accumulates much smaller residual pile deflection (δ _p), than the single pile under one-way cycling. This is because the reverse part of the two-way cycling also generates plastic strain, causing additional softening and strength reduction in the soil surrounding the pile. After each cycling, non-zero bending moment (i.e. locked in moment, or M _L) is retained in the single piles, and the M _L increases with the δ _p. The one-way cycling leads to two times larger M _L than the two-way cycling, as it causes greater δ _p. The maximum M _L in the pile after one-way cycling can be up to 40% of the maximum bending moment induced during the previous cyclic loading stage. After application of jet-grouting surrounding the upper part of the single pile, it greatly reduces degradation of lateral pile stiffness, accumulation of δ _p and therefore development of M _L. Compared to the field measurements, the API (API RP 2A-WSD, recommended practice for planning, designing, and constructing fixed offshore platform-working stress design, 21st edn. API, Washington, 2000) code underestimates the lateral stiffness of the pile under one-way cycling, while overestimates that of the pile under two-way cycling, leading to a non-conservative prediction of bending moment in the latter pile.     

Liquefaction analysis and soil improvement in Beydag dam

Beydag dam is under construction on Kucukmenderes River for irrigation purposes. Due to the scarcity of core material and liquefaction of alluvium at the dam site, the original design was changed to Roller Compacted Concete (RCC) from rockfill dam with claycore. Although the new design was safer, it nearly doubled the cost of the dam, so the owner, State Hydraulic Works of Turkey, (DSI) set out to find more economical but equally safe alternative. Since jet-grouting is a cheap ground improvement tool in Turkey, such an alternative was developed for the ground improvement against liquefaction together with concrete face rockfill dam sitting on top of improved ground. This paper presents a detailed discussion of how the new alternative was developed and evaluated: it discusses the determination of jet grouting pattern, the placement of jet grouted blocks, and the assesment of liquefaction. On one hand the soil cement strength of jetgrout columns, internal friction angle of alluvium and rockfill were important in determining the dimensions of the blocks, on the other hand the location of the blocks were highly affected by the areas where liquefaction occurred. One of the most important parameter that has a considerable influence in delineating the boundary betweeen liquefaction and non-liquefaction was the value of stress reduction coefficient (r _d), being primarily sensitive to the weight of overburden, which is calculated by the height from the face of dam to the depth where the calculation was made. This approach is justified by two-dimensional ground response analysis. Most importantly, this paper shows that there exists an alternative solution for building dams on the liquefaction prone sites without removing alluvium by using a well known jet grouting technique for improving ground at only selected places.     

地铁隧道下穿小河和桥梁的施工方案研究

综合工程经验,对北京地铁5号线过河过桥隧道施工可能采用的4种超前支护方案即水平旋喷桩、全断面深孔注浆、长管棚、加密小导管注浆并辅以临时仰拱进行初步分析,认为加密小导管方案在施工造价、掘进速度和施工影响方面具有优势。采用三维数值模拟方法对长管棚方案和加密小导管方案进行进一步评价并择优。数值模拟结果显示,在不计管棚施工对地层提前扰动的情况下,长管棚方案与加密小导管方案对桥台、桥墩以及小月河河底的影响是相当的,可以认为,加密小导管方案将优于长管棚方案;长管棚、小导管和锁脚小导管承受弯矩较小,锁脚小导管以及隧道拱部的小导管承受轴压力,边墙的小导管既承受轴压力又承受轴拉力,长管棚主要承受轴拉力。     

基于动力学和材料软化特性的边坡渐进破坏特征研究

边坡的失稳是一个从量变到质变的动态渐进破坏过程,此问题也是边坡领域研究的重点与难点之一。在考虑岩土材料软化特性和动力学求解的基础上,建立了边坡渐进破坏仿真的理论框架;利用ABAQUS软件的动力显式求解模块实现了边坡的渐进破坏仿真;根据塑性应变揭露了剪切带的扩展过程,由软化本构确定了滑面材料的分区演化规律,根据等效塑性应变确定了边坡的滑面,通过滑面位置将边坡分为滑体、滑带、滑床,并分别研究了边坡各分区内部特征点运动学变量的发展过程,从而揭示了边坡的渐进破坏过程;基于材料参数沿滑面的时空分布,利用矢量和法得到了边坡不同演化阶段的安全系数。对比该方法与Bishop法确定的滑面位置与安全系数,发现两种方法峰值和残余强度对应的安全系数比较接近,该方法搜索所得滑面位于Bishop法自动搜索的滑面之间,验证了此方法的合理性及可靠性。最后分析了材料软化特征对边坡稳定性的影响,在保持其他参数不变的条件下,增大残余黏聚力,边坡的滑面位置加深,安全系数的初始值减小,安全系数的快速减小阶段有所推迟,并且快速减小阶段经历的时间有所延长,稳定后的安全系数有所增大。保持其他参数不变,增大残余黏聚力对应的等效塑性应变阈值,边坡的滑面位置加深,安全系数的初始值减小,安全系数的快速减小阶段有所推迟,但快速减小阶段经历的时间基本不变,达到稳定的时间有所推迟,同时稳定后的安全系数略微有所增大。     

盾构施工引起地表固结沉降问题的研究

将隧道周围土体视为均质连续各向同性的饱和弹性介质,采用保角变换的方法将含有隧道的半无限平面映射为同心圆环计算域。根据Terzaghi-Rendulic二维固结理论,建立隧道在不透水的情况下周围土体超孔隙水压力分布的控制方程。然后,采用分离变量法计算得到土体超孔隙水压力分布的解析解,最后,根据弹性理论计算得出隧道中线上方地表固结沉降的计算公式。结合算例,分析盾构施工扰动程度、土体渗透系数、土体弹性模量及隧道埋深等因素对隧道中心上方地表处固结沉降的影响。研究结果表明,地表固结沉降的增加值与隧道外侧初始超孔隙水压力值C0的变化量成正比例关系,施工扰动程度越大所引起的固结沉降越大;土体的渗透系数越大固结沉降速度越快,但土体的渗透系数与最终的地表固结沉降量无关;土体的弹性模量越大,最终的地表固结沉降量越小;隧道埋深越深,地表固结沉降所需时间越长,最终的地表固结沉降量也越大。