Application of high-pressure water jet technology and the theory of rock burst control in roadway

This paper puts forward using high-pressure water jet technology to control rock burst in roadway, and analyzes the theory of controlling rock burst in roadway by the weak structure zone model. The weak structure zone is formed by using high-pressure water jet to cut the coal wall in a continuous and rotational way. In order to study the influence law of weak structure zone in surrounding rock, this paper numerically analyzed the influence law of weak structure zone, and the disturbance law of coal wall and floor under dynamic and static combined load. The results show that when the distance between high-pressure water jet drillings is 3 m and the diameter of drilling is 300 mm, continuous stress superposition zone can be formed. The weak structure zone can transfer and reduce the concentrated static load in surrounding rock, and then form distressed zone. The longer the high-pressure water jet drilling is, the larger the distressed zone is. The stress change and displacement change of non-distressed zone in coal wall and floor are significantly greater than that of distressed zone under dynamic and static combined load. And it shows that the distressed zone can effectively control rock burst in roadway under dynamic and static combined load. High-pressure water jet technology was applied in the haulage gate of 250203 working face in Yanbei Coal Mine, and had gained good effect. The study conclusions provide theoretical foundation and a new guidance for controlling rock burst in roadway.

In situ experimental study on TBM excavation with high-pressure water-jet-assisted rock breaking

China’s first high-pressure hydraulically coupled rock-breaking tunnel boring machine(TBM) was designed to overcome the rock breaking problems of TBM in super-hard rock geology, where high-pressure water jet system is configured, including high-flow pump sets, high-pressure rotary joint and high-pressure water jet injection device. In order to investigate the rock breaking performance of high-pressure water-jet-assisted TBM, in situ excavation tests were carried out at the Wan’anxi Water Diversion Project in Longyan, Fujian Province, China, under different water jet pressure and rotational speed. The rock-breaking performance of TBM was analyzed including penetration, cutterhead load, advance rate and field penetration index. The test results show that the adoption of high-pressure water-jet-assisted rock breaking technology can improve the boreability of rock mass, where the TBM penetration increases by 64% under the water jet pressure of 270 MPa. In addition, with the increase of the water jet pressure, the TBM penetration increases and the field penetration index decreases. The auxiliary rock-breaking effect of high-pressure water jet decreases with the increase of cutterhead rotational speed. In the case of the in situ tunneling test parameters of this study, the advance rate is the maximum when the pressure of the high-pressure water jet is 270 MPa and the cutterhead rotational speed is 6 r/min. The technical superiority of high-pressure water-jet-assisted rock breaking technology is highlighted and it provides guidance for the excavation parameter selection of high-pressure hydraulically coupled rock-breaking TBM.

Operation optimization of plugged screen cleanup by rotary water jetting

The rotary water jetting is one of the most important techniques for horizontal well cleanup.The jet flow is used to remove plugging particles from sand control screens to recover their permeability.Currently,the operation optimization of this technique depends mainly on experience due to absence of applicable evaluation and design models for removing plugging materials.This paper presents an experimental setup to simulate the cleanup process of plugged screens by rotary water jetting on the surface and to evaluate the performance of a jetting tool.Using real plugged screens pulled from damaged wells,a series of tests were performed,and the qualitative relationships between the cleanup efficiency and various operational parameters,such as the type of fluids used,flow rate,mode of tool movement,etc.,were obtained.The test results indicated that the cleanup performance was much better when the rotary jetting tool moved and stopped periodically for a certain time than that when it reciprocated at a constant speed.To be exact,it was desirable for the rotary jetting tool to move for 1.5-2 m and stop for 2-4 min,which was called the ＂move-stop-move＂ mode.Good cleanup performance could be obtained at high flow rates,and the flow rate was recommended to be no lower than 550-600 L/min.The test results also indicated that complex mud acid was better than clean water in terms of cleanup performance.Good cleanup efficiency and high screen permeability recovery could be achieved for severely plugged screens.Rotary jetting is preferred for the cleanup of horizontal wells with severely plugged screens,and the screen permeability recovery ratio may reach 20％ if optimized operation parameters were used.

Dynamic effects of high-pressure pulsed water jet in low-permeability coal seams

Mine gas extraction in China is difficult due to the characteristics such as micro-porosity,low-permeability and high adsorption of coal seams.The pulsed mechanismof a high-pressure pulsed water jet was studied through theoretical analysis,experimentand field measurement.The results show that high-pressure pulsed water jet has threedynamic properties.What's more,the three dynamic effects can be found in low-permeabilitycoal seams.A new pulsed water jet with 200-1 000 Hz oscillation frequency andpeak pressure 2.5 times than average pressure was introduced.During bubble collapsing,sound vibration and instantaneous high pressures over 100 MPa enhanced the cuttingability of the high-pressure jet.Through high-pressure pulsed water jet drilling and slotting,the exposure area of coal bodies was greatly enlarged and pressure of the coal seamsrapidly decreased.Therefore,the permeability of coal seams was improved and gas absorptionrate also decreased.Application results show that gas adsorption rate decreasedby 30%-40%and the penetrability coefficient increased 100 times.This proves that high-pressurepulsed water is more efficient than other conventional methods.

高压旋喷注浆技术对桩土性能影响分析

以水电站软土地基进行注浆成桩项目为例,探讨了高压旋喷压力对土体强度的影响,同时研究了不同旋喷压力下成桩的荷载位移曲线。研究表明,土体的单轴抗压强度随着高压喷射灌浆压力的增加而增加,同时土体抗压强度与抗剪强度之间呈明显的线性相关性,拟合度高达0.99;高压旋喷桩的性能与其喷射压力正相关。

高压旋喷桩技术应用于坑底加固的实效研究

为有效应对深基坑工程中出现的沉降挑战,以玉环万达广场的大型商业综合体建筑为例,采用高压旋喷法技术进行坑底加固处理。首先通过坑底加固设计计算确定桩长为3.5m、桩径0.55m、桩间距为1.124 m,加固区域总共布置64根。然后从钻机就位、钻孔施工、灰浆制备及旋转喷浆对高压旋喷桩施工工艺流程进行全面的分析。最后对该建筑项目的沉降进行了监测,对比两个季度的数据得出高压旋喷桩在深基坑工程中的加固效果显著。这一系统性的监测与分析流程,旨在全面评估高压旋喷法的实施效果,为类似工程提供宝贵的经验参考。

第三系半成岩富水砂岩隧道水平高压旋喷桩加固机理及参数分析

第三系半成岩具备弱胶结、遇水软化等特征,隧道建设时易诱发涌水突泥和坍塌等地下地质灾害。依托云南临清高速公路王家寨隧道,结合现场地质条件与现有工程案例,采用水平高压旋喷桩对软弱围岩进行超前预加固。结合地基梁理论解析、数值模拟与现场监测方法,研究第三系半成岩水平高压旋喷桩加固机理及不同桩体参数对围岩加固效果的影响,并给出桩体参数建议范围,为类似工程提供参考。研究表明:旋喷桩加固后解析解与数值解的剪力与弯矩分布规律较为一致,在开挖未支护段桩体所受弯矩、剪力最大,最易发生断裂破坏;当围岩水压力在300 kPa时旋喷桩体最大拉应力达598.21 kPa,接近桩体极限抗拉强度,水压力小于300 kPa时水平旋喷桩能有效发挥梁、拱协同作用,拱棚效应与阻水效果显著,能将围岩压力传递给桩体后端及拱肩、边墙处,围岩沉降与地下水压得到有效控制,这与现场监测结果基本吻合;桩径、桩长、咬合厚度及搭接长度变化对桩体应力影响较大,影响程度为咬合厚度>桩长>搭接长度>桩径,建议在第三系半成岩富水砂岩隧道围岩水压力小于300 kPa进行超前预加固时,水平旋喷桩桩体参数范围为桩径65~70 cm、桩长10~13 m、咬合厚度25 cm、搭接长度3~4 m。

复杂环境中矩形顶管始发端地层加固方案优化研究与应用

矩形顶管的始发阶段是矩形顶管施工中风险最高的施工阶段,在施工过程中,必须在始发前对始发端地层进行预加固处理。城市核心区域由于受到地面和地下建筑物、管线的影响,经常遇到加固盲区、加固不到位的问题。基于此,本研究总结提出了一种旋喷桩加固结合钢板桩防护的施工方法,在始发基坑洞门处围护结构外侧,密贴围护结构打设钢板桩,结合旋喷加固、洞门凿除等工艺改进措施,有效降低始发端地层施工风险,保证工程自身和周边环境安全。

高压旋喷桩复合地基承载力研究

为促进符合地基承载力的提升,引入高压旋喷桩施工工艺,开展在该工艺应用下符合地基承载力的探究。以惠清项目桥梁桩工程施工建设状况为背景,高压旋喷桩复合地基施工处理技术方案形成、建立高压旋喷桩复合地基承载力计算模型。通过形成高压旋喷桩,开展高压旋喷桩施工与加固工作,最后对复合地基承载力进行计算。通过研究得出,高压旋喷桩的应用可以有效促进复合地基承载力的提升,并且大部分承载力作用在高压旋喷桩的上部。

三轴搅拌桩组合高压旋喷桩入岩落底式止水帷幕施工技术

某房建深基坑工程支护形式采用排桩+落底式止水帷幕,场地地质条件上部为富水深厚砂层,下部为强风化岩层,止水帷幕需穿透强风化岩0.5 m,以隔断强透水层。通过对地质情况及现有设备条件分析,采用大功率桩机先行施工三轴搅拌桩,养护后进行桩体质量抽芯验证,再针对不同缺陷程度采用高压旋喷桩分别进行补强的组合工艺施工止水帷幕。基坑开挖结果表明,该落底式止水帷幕效果良好,能有效隔断强透水层,与灌注排桩结合形成深基坑支护结构体系具有较高的经济性、适用性。

软土路基高压旋喷桩基础施工技术研究

介绍了高压旋喷桩加固软土路基的相关理论和技术细节,涵盖了高压旋喷桩的加固原理、施工工艺以及质量控制方案等方面的内容。结合江门市某软土地基公路工程案例,对临近高压线塔的软土路基高压旋喷桩施工过程中的难点和重点进行分析和探讨。

基于堤防工程地基加固高压旋喷桩优选施工参数研究

在南方某堤防工程中采用高压旋喷桩施工对软土地基进行加固处理,通过分析软土地基工程特性和高压旋喷桩施工原理,设置三种工况参数进行试验桩施工,对比试验桩的实际桩长、桩径、垂直度、复合地基承载力等参数,将喷浆压力25MPa、提升速度0.15m/min、水灰比0.8作为优选施工参数,对拟建场地工程桩进行指导施工,可提升高压旋喷桩工程桩整体质量和软土地基加固效果。

高压旋喷注浆在岩溶地基加固处理中应用研究

我国分布有大量的岩溶地貌,是世界上岩溶发育最为典型的区域之一,岩溶类型多样复杂,而正因为这些岩溶地貌的复杂与较多的不可控因素,给这些区域内进行工程建设造成诸多难题。高压旋喷注浆法是采用高压水流连续和集中的作用在土地上,对土层产生巨大的冲击破碎和搅动作用,通过注入浆液,使浆液和土拌合均匀并凝固为新的固结体,从而达到对不良地基加固的效果。本文结合长株潭城际铁路车辆段工程,研究分析岩溶不良地质条件下,就单管高压旋喷注浆地基加固设计思路、具体方案及主要技术等进行深入研究,对类似地质条件下的工程提供参考经验。

某格形钢板桩码头升级改造方案三维有限元数值分析

某格形钢板桩码头升级改造工程,前沿港池疏浚后改变了格形墙体前板桩埋入深度,影响码头结构稳定性。为了探究改造后格形钢板桩稳定性和破坏形态,利用有限元软件MIDAS GTS,构建适用于格形钢板桩结构稳定性分析的三维有限元数值模型,通过对最不利工况下格形钢板桩改造前后的变形、受力、整体稳定性对比分析,提出复合地基和抗滑桩加固相结合的格形钢板桩码头改造方案。结果表明,码头加固前后的格形钢板桩整体变形、土压力分布、结构内力和地基反力分布基本一致。

低渗透性污染场地高压旋喷修复药剂迁移特性数值模拟分析

近年来,高压旋喷注药修复技术在低渗透性污染场地中得到广泛应用,药剂注入后在孔周土体中的迁移规律值得深入探讨。考虑分子扩散、机械弥散、对流、颗粒迁移等条件,对高压旋喷注药孔周围地层的药剂时空分布进行有限元数值模拟。模拟结果表明:高压旋喷产生的高速流动溶液引起土体内部细小颗粒迁移,导致渗透系数增大并影响药剂弥散和对流;随着注药压力升高,土体渗透系数增大,药剂迁移位置更远,场地修复区域面积扩大;在高注药压力条件下,渗透系数变化较小,修复面积无明显变化。因此,提高注药压力有助于扩大低渗透性场地的修复面积,但过高压力将使功效降低。研究成果可为低渗透性场地的高压旋喷注药修复设计提供理论支撑。

帷幕灌浆结合高压旋喷灌浆技术在茶根水库主坝加固中的应用

介绍了茶根水库主坝的工程概况及存在的渗漏问题,对大坝帷幕灌浆和高压旋喷灌浆的布孔设计、灌浆材料、灌浆方法、高喷水压、用水量、灌浆压力、浆量及浆液比重以及施工质量控制等问题进行了分析与论述。

旋喷脱硫技术在液化气脱硫中的工业应用

介绍了旋喷脱硫技术在某石化企业产品精制装置液化气脱硫中的工业应用情况。该技术应用后,有效解决了该石化企业产品精制装置液化气脱硫塔处理能力偏低,脱硫率不理想,产品中硫化氢含量不稳定的问题;有效解决了因液化气中硫化氢含量超标,导致后续脱硫醇系统碱液、催化剂消耗过大,脱硫醇效果差的问题;有效解决了液化气夹带胺液的问题。

旋喷技术在延迟焦化装置罐顶气环保治理中的工业应用

介绍了旋喷技术在某石化企业延迟焦化装置冷焦水罐和切焦水罐顶部气体环保治理中的工业应用情况。该技术应用后,脱除了冷焦水罐和切焦水罐顶部气体中的硫化氢,解决了罐顶气恶臭问题和后续VOCs处理设施硫化氢腐蚀问题;脱除了冷焦水罐和切焦水罐顶部气体中的焦粉,减缓了后续VOCs处理设施易堵塞的问题,保证了整个系统持续平稳的运行。冷焦水罐和切焦水罐顶部气体经旋喷水洗和旋喷脱硫后,焦粉脱除率≥99%,净化罐顶中总硫含量≤10 mg/m^(3),液滴含量≤50 mg/m^(3)。

高压旋喷扩径锚索在深厚填土基坑中的研究与应用

众所周知对于支护深度超过15m且土层为深厚填土层的基坑,支护形式往往采用大直径的支护桩结合内支撑(斜撑)进行支护,圬工量大且影响后期主体结构施工,如何在深厚填土中发挥锚索的有效拉拔力一直是岩土工程界研究的方向。高压旋喷扩径锚索是一项新兴的支护方法,主要是运用高压旋喷技术对软弱土层进行处理,将钢绞线放置孔内后喷射水泥浆形成锚拉体系,从而在钢筋锚固段底部产生扩大头锚固体,它不同于普通锚索,能够适用于各种地层。本文以成都某深厚填土基坑为例,通过多组原位试验研究分析不同锚固长度的旋喷扩体锚索的实际抗拔力,让设计人员对填土中旋喷扩径锚索的实际抗拔力有了更进一步的了解,为填土中旋喷扩径锚索的拉力值提供了工程类比经验。

高压旋喷桩施工技术在道路路基加固中的应用与效果评估

本文以G6京藏高速公路刘寨柯至响泉口段路基为加固对象,使用高压旋喷桩施工技术的具体操作方法与施工要点信息,并使用单桩承载力这一指标,评估高压旋喷桩施工技术在道路路基加固中应用效果。评估结果显示:高压旋喷桩施工技术使用后,G6京藏高速公路刘寨柯至响泉口段路基单桩承载能力、单桩无侧限抗压强度均合格,说明高压旋喷桩施工技术在道路路基加固中应用效果显著。