Grouting theories and technologies for the reinforcement of fractured rocks surrounding deep roadways

Grouting is an effective method to improve the integrity and stability of fractured rocks that surround deep roadways.After years of research and practice,various theories and a complete set of grouting technologies for deep roadways with fractured rocks have been developed and are widely applied in Chinese coal mining production.This paper systematically summarizes and analyzes the research results concerning the theory,design,materials,processes,and equipment for the grouting and reinforcement of fractured rocks surrounding deep roadways.Specifically,in terms of grouting methods,pregrouting,groutingwhile-excavation,and postgrouting methods are explored;in terms of grouting theory,backfill grouting,compaction grouting,infiltration grouting,and fracture grouting theories are studied.In addition,this paper also studies grouting borehole arrangement,water-cement ratio,grouting pressure,grouting volume,grout diffusion radius,and other grouting parameters and their determination methods.On this basis,this paper explores the physical and mechanical properties of organic and organic-inorganic composite grouting materials,and assess grouting reinforcement quality testing methods and instruments.Taken as the field cases,the application of pregrouting in front of heading faces,groutingwhile-excavation,and postgrouting in the Kouzidong coal mine are then introduced,and the effects of the grouting reinforcements are evaluated.This paper proposes a development direction for grouting technology based on problems existing in the grouting reinforcement of fractured rocks surrounding deep roadways.

Theory,technology and application of grouted bolting in soft rock roadways of deep coal mines

The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.

松散地层脉动与稳压灌浆室内试验研究

开展松散地层控制灌浆工艺研究具有重要的工程实践意义。开发了一套室内松散地层灌浆模拟试验装置,可模拟受灌体弹塑性边界,对比进行稳压灌浆与脉动灌浆试验。试验结果表明,在相同围压(0.2 MPa)、水固比(0.6)、不同灌浆压力(0.1,0.2,0.4 MPa)条件下,脉动灌浆灌后结石体7 d强度明显优于稳压灌浆,且强度值分布较均匀。电镜扫描表明,脉动灌浆后的土体呈团状结构,较常规灌浆后的絮状结构更紧密。脉动灌浆参数影响试验表明,采用较大的脉动灌浆压力有利于受灌体挤密,但压力过大更易劈裂扩散,造成浆脉变薄、结石强度降低;采用较小的水固比不利于浆液的扩散,但水固比过大会导致结石体厚度变薄、强度降低。试验论证了松散地层灌浆采用脉动灌浆工艺更加适宜,但需合理控制灌浆压力和水固比。

软土地区超长抗拔桩成桩选型研究

对软土地区长抗拔桩中常用的常规直桩、扩底桩、注浆直桩的承载力性状进行了比较分析,研究了不同桩型的荷载传递规律和承载力提高机理,并引出其荷载-位移的理论计算公式,认为抗拔桩存在"有效桩长"。通过对某沿海城市不同超长抗拔桩的现场抗拔试验,分析比较了各种桩型在30mm上拔位移控制值下的单桩承载力和桩侧摩阻力分布规律,认为超过"有效桩长"的设计是不经济的,注浆直桩可以提高安全系数,宜优先选用注浆直桩。

“控压起钻+重浆帽”技术在裂缝储层中的应用与认识

针对裂缝性储层,常规重浆吊灌起钻存在较大井下压力波动,不但钻井液漏失量大,还可能诱发严重溢流。全程带压起钻方式虽然能减小起钻抽吸压力,保持井底压力平衡,但需要使用带压起下钻装置,反而增加了作业风险。“控压起钻+重浆帽”方式结合了常规重浆吊灌和全程带压起钻的优点,既可减小起钻抽汲压力,降低钻井液漏失量,还可避免因使用带压起下钻装置增加作业风险。文章简要介绍了“控压起钻+重浆帽”方式工艺流程,重点描述了重浆帽注入量、重浆帽注入井段、压水眼重浆设计。现场应用表明,“控压起钻+重浆帽”方式安全性好、效率高、成本低,是目前裂缝储层起下钻作业最安全、最有效的方式。

大直径盾构掘进风险分析及对特大直径盾构挑战的思考

目前,基于建设规模和设计功能的需求,特大直径盾构已多次应用于铁路、公路、城市轨道交通、地下管廊等领域隧道工程建设。初步统计了国内外15.5 m以上的特大直径盾构隧道工程,总结了大直径盾构在掘进过程中的主要风险及常见问题,包括主轴承损坏失效、盾构管片拼装脱出盾尾后上浮、刀具磨损随盾构直径增大而加剧、刀盘前泥饼粘结、渣土滞排、刀盘升温等,并结合案例分析其原因。针对特大直径盾构带来的事故风险,从土压盾构与泥水盾构主轴承密封问题、管片盾尾脱出后上浮风险、常压刀盘与常规刀盘的选择、泥饼粘结和渣土滞排难题、预探前方复杂地质、海中基岩爆破及注浆固结辅助处理等方面提出思考和建议。

基于分布式后压浆的灌注桩承载力试验研究

介绍了一种灌注桩分布式后压浆工艺及实现方法,相比于传统后压浆工艺,分布式压浆工艺利用声测管实现桩端、桩侧组合压浆,解决了传统后压浆装置出浆口断面间距大、压浆孔开塞率低及浆液分布不均匀等问题,提高了浆液利用率,实现了声测管的一管两用,极大减少了后压浆预埋管数量,提升了施工效率。基于河南省安罗高速黄河特大桥项目3根大直径灌注桩,利用桩基自平衡承载力测试法开展压浆前后承载力试验,对比研究了不同压浆工艺对桩基承载力提升的影响,结果表明:分布式压浆工艺在同等压浆量的情况下承载力提升优于传统压浆;分布式后压浆工艺相比传统后压浆工艺,施工更为便捷,浆液分布更均匀、浆液利用率更高,更加适用于大直径超长灌注桩的后压浆施工。

柬埔寨甘再水电站大坝坝基固结灌浆实践与探索

由于柬埔寨甘再水电站大坝坝基地质条件复杂,为提高大坝坝基承载力,探究合理的固结灌浆方法和灌浆参数,分别进行了G IN灌浆法和常规灌浆法2种固结灌浆试验,通过试验,探索出了适合于甘再水电站大坝基础固结灌浆的方法及合理的灌浆参数。

繁华城区深大异型基坑施工技术

针对朝阳门站1号换乘厅的异型基坑,周边环境复杂,对控制基坑变形有较高要求的特点,施工中采用肥槽土体注浆加固等施工技术,保证了基坑及周边环境的安全,为类似工程积累了经验。

三峡工程三期土石围堰防渗墙施工工艺试验(Ⅱ)

为确保防渗墙墙体防渗效果和施工工期要求 ,在防渗墙大规模施工前进行了振孔高喷、常规高喷、钻喷一体化和自凝灰浆防渗墙等成墙工艺的现场试验 。

三峡工程三期土石围堰防渗墙施工工艺试验(Ⅰ)

为确保防渗墙墙体防渗效果和施工工期要求 ,在防渗墙大规模施工前进行了振孔高喷、常规高喷、钻喷一体化和自凝灰浆防渗墙等成墙工艺的现场试验 ,试验结果说明四项成墙工艺均可用于三峡工程三期土石围堰防渗墙。

追求隧道工程与地质体的和谐——矿山法隧道工程若干热点问题探讨

随着矿山法隧道工程修建理念从对围岩“被动防范”更新为“主动控制”,隧道工程师们的注意力聚焦于监控量测、围岩改良、双重型衬砌结构的整合性和设计计算模型等热点问题,文章对此进行了探讨。同时,针对高地应力背景的挤压性软弱岩体和高水头地下水的两种特异地质环境的隧道工程难题,阐述了以“屈让原则”代替“对抗原则”,分别采用“围岩锚固+恒阻支护”和“围岩注浆+衬砌疏排”的处治手段体现隧道工程和地质体和谐的理念。