崔家冲隧洞软弱围岩注浆工法的研究应用

长沙引水及水质环境工程崔家冲隧洞要穿越区域性高棱山压扭性断层F86,断层宽度达100余米,长度达1000余米,洞顶以上地表覆盖层达110 m,其规模为同类工程所罕见。由于断层破碎带岩体强度低,透水性好,穿越断层破碎带洞段的施工成为工程建设中的重点和难点。所以隧洞在施工过程中需采用多种方法穿越众多的不良地质段。主要介绍和探讨了该隧洞穿越F86断层破碎带所采用的超前预注浆技术、超前支护技术及长管棚施工技术,为今后在类似工程中提供施工借鉴。     

海底透水通道发育带隧道施工注浆技术研究

通过对海底透水通道的特征分析,采用裂隙超前预注浆和裂隙补充注浆方法成功地解决了裂隙注浆堵水难题,为海底隧道安全施工提供了保障。提出了适于海水条件下的裂隙注浆原则、参数、设备、方法、工艺、材料及注浆效果检查方法,并成功地应用于胶州湾海底隧道穿越断裂破碎带时裂隙岩体注浆实践,其研究结果可为类似工程提供参考     

Deformation behaviour of a large underground cavern

Summary The Imaichi underground power station, with a cross sectional area of 1420 m², which is now under construction by Tokyo Electric Power Co., Inc., is one of the largest underground caverns in the world. Due to the considerable depth of the over-burden of 400 m, the horseshoe-shaped section was adopted for the first time in Japan to minimize excesive stress concentration on the surrounding bedrock and keep loosened zones to a minimum.The bedrock consists of sandstone, slate, siliceous sandstone and breccia. The rock is generally hard and compact, with few fractured zones which may have an adverse influence on the excavation of the cavern.The supporting system of the cavern consists of prestressed rock anchors, rock bolts and shotcrete.Approximately 800 instruments, mainly multiple stage extensometers, were used to monitor behaviour of the surrounding rock during excavation of the cavern. With the exception of some cracks which occurred in a portion of the shotcrete when about half the height of the cavern had been excavated, excavation work was completed without any major trouble. In spite of the symmetrical shape of the cavern, the deformation behaviour of the surrounding rock during excavation was remarkedly asymmetric. The reason for this was concluded to be the peculiar deformation behaviour exhibited by Breccia during stress relief, as shown by in-situ rock tests, etc., and analysis of deformation data after completion of the excavation work.     

劈裂注浆抬升既有管道效果分析及工程应用

地铁车站施工中常穿越大量的市政管道,由于隧道开挖引起地层损失和地表沉降,地下管道将会发生变形,往往影响地铁施工,注浆是对地下管道进行沉降控制的主要技术措施。以北京地铁黄庄站下穿热力管道抬升注浆工程为研究对象,利用三维有限差分数值方法分析了新建车站开挖引起超大管道的变形特征。结果表明,在抬升区注浆单元施加膨胀压力可以较好模拟注浆抬升既有管道的效果;采用应变软化模型,可以有效模拟土体材料的弹塑性力学行为,反映注浆完成后浆脉的固结和周围土体的湿陷作用。对比注浆抬升模拟计算和沉降监测结果,验证了有限差分数值方法模拟劈裂注浆抬升管道过程的正确性和有效性。同时模拟分析注浆抬升管道的影响因素,获得了一些规律性的认识,为劈裂注浆抬升地下管道工程的施工和设计提供指导。     

地面大直径应急救援钻孔成孔工艺设计与分析

地面大直径钻孔可作为井下被困人员的逃生通道,是矿山事故造成人员被困井下时重要的应急救援方案之一。而常规大直径工程孔以泥浆正循环、多级扩孔工艺为主成孔,无法满足救援要求。着眼于大直径孔救援逃生目的,阐明包括精准透巷、优化孔身结构、高效成孔和安全透巷等四项成孔工艺设计原则;以此为指导,针对覆盖层钻进、二开基岩层钻进、下套管及固井具体施工情况,分析了全套管钻进、导向孔下导管钻进及集束式潜孔锤扩孔钻进、浮力法下套管及内插法固井等技术;借用巷道围岩松动圈及塑性区成熟理论,视透巷钻进所破坏的塑性区岩体为潜在垮落体,进行顶板稳定校核,提出了安全透巷距离及位置等关键参数设计选取方法,为地面大直径应急救援钻孔施工提供技术支持。      

暗挖隧道杂填土地层马头门支护与开挖方法分析

城市隧道暗挖施工期间拱顶以及地表的沉降量对施工安全、工程功能及城市道路正常运行具有重要意义。浅埋暗挖法施工中各类马头门的施工因其受力转换特殊往往是施工过程中关注的重点。北京地铁7号线某区间暗挖隧道马头门处于竖井明挖施工的回填土中,其土质情况复杂、暗挖不确定性因素多。为保证隧道施工和周围构筑物的安全,须对处于回填土范围内竖井马头门的破除与开挖方案进行研究。本文根据地表勘察钻探和超前探测所获取的地层资料和工程设计资料,应用FLAC3D软件对马头门破除时的两个支护方案进行了对比分析。施工实践与理论分析均表明,采用无收缩（WSS）深孔注浆方案的地表沉降量约是超前小导管支护方案沉降量的1/2～1/3。     

基于Hoek-Brown强度准则的隧道软弱围岩稳定性分析

因长期遭受地质作用和构造力的改造作用,地下岩体中存在大量的软弱破碎带,隧道开挖穿越这一地带很容易出现较大的变形,甚至出现塌方等事故。论文采用TGP超前地质预报与掌子面围岩调查相结合的方法进行隧道掌子面及前方未开挖岩体的精细化地质调查,获取了隧道围岩的Hoek-Brown参数。采用FLAC3D数值模拟方法,分析了破碎带围岩在既定支护条件下的稳定性,并与现场监测数据进行对比,验证此方法的正确性。研究结果表明,数值模拟结果与实际监测结果较为吻合,可以将此方法用于指导未开挖段隧道的稳定性预测,以确保隧道掘进过程的施工安全。     

双液注浆技术在杭州市天城广场工程中的应用

针对杭州市天城广场工程在基坑开挖过程中地下连续墙接缝处局部出现渗漏水的情况,为确保基坑开挖及周边建筑物的运作安全,采用水泥-水玻璃双液注浆技术对该部位出现的渗漏进行技术处理。分析了渗漏的原因,介绍了水泥-水玻璃双液注浆工艺及施工技术措施。     

1113机采工作面突水分析与治理

2006年4月19日,山东珑山实业有限公司1113机采工作面发生井下突水事故,突水量300m^3／h。通过水质化验、奥灰孔水位观测等资料分析,得出了突水水源为奥陶系岩溶水,突水的原因是断层、矿山压力及高水压三大因素综合作用波及到了底板奥陶纪石灰岩含水层的结论。在注浆治理中,本着截流封源的思路,在井下先后施工了两个注水钻孔。在注1号钻孔失败后,及时调整了方案,自1111机道7号点,沿方位260°3′44″掘专门堵水平巷130m,重新布置了注2号钻孔,修改了终孔落脚点,结果注2号孔准确命中目标。通过单液水泥注浆技术注入70．3t水泥,浆液的水灰比为：2：1～1．5：1,工作面水量最后稳定在20．16m^3／h,从而顺利完成了注浆堵水任务,为今后井下打钻注浆堵水提供了有益的借鉴。     

斜井二次涌水原因分析及注浆治理措施

山西潞安集团黑龙煤矿副斜井在经过迎头预注浆后,在预注浆段内掘进时再次发生涌水现象,导致井筒被淹。分析其主要原因为初次注浆形成的软粘土与浆液共同的裂隙充填体稳定性差。对于涌水裂隙采取分流泄压再堵水的总体治理方案,即变不可控涌水为可控水后再注浆处理。涌水点注浆堵水严格控制注浆压力,采用水泥-水玻璃双液浆。通过布设检查孔对注浆效果进行检查分析注浆质量较好,为类似有软粘土充填裂隙岩体的注浆治理提供借鉴。     

Stability of expansive cement grout borehole seals emplaced in the vicinity of underground radioactive waste repositories

An expansive cementitious borehole plug emplaced in an underground opening in the vicinity of an underground nuclear waste repository may generate radial stresses on the walls of the opening due to an axial stress applied to the borehole plug and due to plug swelling. As these radial stresses may lead to the tensile fracturing of the rock, minimizing or preferably eliminating tensile stresses in rock is particularly important to preserve waste containment. Presented in this paper are the theoretical radial (normal) stress distribution and tensile strength in a borehole plug–rock system due to combined axial, thermal and lateral loading, along with analyses of plug–rock mechanical interactions in regards to borehole stability against tensile fracturing.     

Fracture-zone conditions on a recently active fault: insights from mineralogical and geochemical analyses of the Hirabayashi NIED drill core on the Nojima fault, southwest Japan, which ruptured in the 1995 Kobe earthquake

An 1800-m-deep borehole into the Nojima fault zone was drilled at Nojima-Hirabayashi, Japan, after the 1995 Hyogo-ken Nanbu (Kobe) earthquake. Three possible fracture zones were detected at depths of about 1140, 1300, and 1800 m. To assess these fracture zones in this recently active fault, we analyzed the distributions of fault rocks, minerals, and chemical elements in these zones. The central fault plane in the shallowest fracture zone was identified by foliated blue-gray gouge at a depth of 1140 m. The degree of fracturing was evidently greater in the hanging wall than in the footwall. Minerals detected in this zone were quartz, orthoclase, plagioclase, and biotite, as in the parent rock (granodiorite), and also kaolinite, smectite, laumontite, stilbite, calcite, ankerite, and siderite, which are related to hydrothermal alteration. Biotite was absent in both the hanging wall and footwall across the central fault plane, but it was absent over a greater distance from the central fault plane in the hanging wall than in the footwall. Major element compositions across this zone suggested that hydrothermal alteration minerals such as kaolinite and smectite occurred across the central fault plane for a greater distance in the hanging wall than in the footwall. Similarly, H₂O+ and CO₂ had higher concentrations in the hanging wall than in the footwall. This asymmetrical distribution pattern is probably due to the greater degree of wall–rock fracturing and associated alteration in the hanging wall. We attributed the characteristics of this zone to fault activity and fluid–rock interactions. We analyzed the other fracture zones along this fault in the same way. In the fracture zone at about 1300 m depth, we detected the same kinds of hydrothermal alteration minerals as in the shallower zone, but they were in fewer samples. We detected relatively little H₂O+ and CO₂, and little evidence for movement of the major chemical elements, indicating little past fluid–rock interaction. In the fracture zone at about 1800 m depth, H₂O+ and CO₂ were very enriched throughout the interval, as in the fracture zone at about 1140 m depth. However, smectite was absent and chlorite was present, indicating the occurrence of chloritization, which requires a temperature of more than 200 °C. Only smectite can form under the present conditions in these fracture zones. The chloritization probably occurred in the past when the fracture zone was deeper than it is now. These observations suggest that among the three fracture zones, that at about 1140 m depth was the most activated at the time of the 1995 Hyogo-ken Nanbu (Kobe) earthquake.     

3D numerical model for dynamic loading-induced multiple fracture zones around underground cavity faces

Three dimensional numerical modelling was used to examine the fracture responses around cavities in rock masses experiencing the stress of excavation. In addition to the primary fracture zone in the near-field, numerical modelling generated a second fracture zone in the far-field and an elastic non-fracture zone between the two fields, i.e., fracture and non-fracture zones occurred alternately around a deep cavity. Further research illustrated that the dynamic load and static stress gradient are two necessary precursors for a far-field fracture in the excavation process. Neither quasi-static loading nor homogeneous stress conditions could induce a far-field fracture. A simple theory is introduced, suggesting that multiple fracture zones occur during excavation due to both the initial stress gradient and the dynamic load. This finding indicates that it may be possible to induce continuous rock fractures in deep underground rock masses by employing optimal excavation methods to generate multiple contiguous fracture zones.     

煤矿井下水砂突涌钻孔封孔技术研发与应用

桑树坪煤矿采取地面注骨料和井下注浆技术治理奥灰(奥陶纪灰岩)岩溶陷落柱时,施工的3个常规检查钻孔出现严重的水砂突涌现象,封孔难度极大,采取向孔内下入木楔、反丝止浆塞等方法均封孔失败。针对此难题,提出带压顶替注浆封孔技术,首先,向孔内注入大于套管体积的清水以确保孔内通畅,避免砂粒填充至套管内,导致封孔深度未达到套管以下稳定岩层;之后,采取低泵量向孔内多次循环注入大于套管体积的稀水泥浆;最后,待水泥浆凝固后,采取小直径钻头钻进至套管外以检查大孔径钻孔的封孔质量。该技术成功应用于3个常规检查钻孔封堵工程,实践发现:先期注浆封孔水泥浆液水灰比宜选取1︰1,单次候凝时间宜选取3~4 d,延长水泥浆候凝时间,可提高钻孔封孔质量。此技术适用于井下狭小空间作业,可防止孔口涌水涌砂,避免孔内水砂高速流动,确保封孔质量及人员安全,为封堵类似水砂突涌钻孔提供技术借鉴。      

节理岩体中隧道开挖与支护的数值模拟

由于节理、断层等不连续面的存在造成岩体变形的不连续性,并且这些不连续面对岩体变形、应力等力学行为造成重要影响。对已有的非连续变形分析程序进行了两点改进,应用改进的程序模拟了节理岩体中隧洞开挖与支护的过程,研究了不同节理倾角岩体的应力分布特性、开挖后隧洞围岩的变形和应力分布规律以及支护后衬砌的变形与应力特点。研究结果表明,节理倾角对节理岩体系统的应力和变形有着直接的影响,并且影响着隧洞开挖后的内空收敛效应;隧洞开挖顺序对围岩的变形和稳定也有重要影响。改进后的非连续变形分析方法和程序可以用来分析复杂节理岩体系统中隧洞的开挖与支护。     

锦屏一级电站尾水调压室大角度上仰孔锚索施工

锦屏一级水电站地下厂房尾水调压室顶拱发育有f14、f18断层及煌斑岩脉,开挖后出露断层及其影响带岩体破碎,风化强烈,围岩不稳定,为了洞室稳定及施工安全,设计采用预应力锚索进行加强支护。介绍了尾水调压室大角度上仰孔锚索的施工方法。     

Evaluation of the Effect of Fault on the Stability of Underground Workings of Coal Mine through DEM and Statistical Analysis

The rock mass around an excavation is generally traversed by different geological discontinuities such as faults, folds, slips, joints, etc. Fault is one of the major geological discontinuities which creates lot of difficulties during underground winning of coal. Entire stress regime and ground conditions in the formation are altered in and around the faults. Faults also impose detrimental effects by introducing impurities, including clay and various forms of mineral matter into the coal seams; opening of pathways for the influx of water and gas into the underground workings; displacing the coal seams upward/downwards making the coal seams difficult or sometimes impractical to mine. Appropriate evaluation of the effect of the fault on the stability of the underground workings is a requisite for safe design of the underground mining structures. In this paper, a study has been carried out to assess the effect of the fault on the stability of underground coal mines by numerical simulation with distinct element method (DEM). On the calibrated DEM model, parametric study has been performed by varying the selected parameters, the dip and the friction angles of the fault. The analysis of variance (ANOVA) shows that both the factors have statistically significant effect on the strength of the coal pillar. Similarly, the displacement of the immediate roof and the height of the disturbed strata are evaluated by the DEM modelling and statistical analysis when the fault passes through the middle of the gallery. The results of ANOVA for both cases indicate that the both factors have significant effect on the displacement of the immediate roof and the height of the disturbed strata. It is obtained from the study that the low angle fault causes high instability in the immediate roof. The paper has been supplemented with the field observations where instability in underground roadways of a coal mine in India is caused by the fault. It was observed in VK-7 incline mine of Singareni Collieries Company Limited, India that there was sudden failure of immediate roof of a roadway where a low angle fault crosses the middle of the roadway. The findings of the paper help to understand the behaviour of the coal pillar and the surrounding rock mass in the presence of the fault. The study would also help to take appropriate decisions about the unstable regions of the working safeguarding safety in underground coal mines.     

掘进巷道突水溃砂高压扰动注浆技术与应用

为了对弱胶结地层条件下的掘进巷道突水溃砂进行治理,以宁东煤田麦垛山煤矿2煤大巷掘进期间突水溃砂为研究对象,针对地面治理工程量大、周期长、井下常规治理风险高等问题,采用井下挡水墙建造、高压扰动注浆、钻注一体化和孔口控压保浆技术,完成了突水溃砂点封堵体的构筑。结果表明:通过在巷道内建造挡水墙,可以有效控制注浆期间的水砂淹没范围,经过对挡水墙及其围岩强度的核算,挡水墙能够至少抵抗1.64 MPa的压力,大于顶板含水层1.2 MPa的水压。首先在距离突水溃砂点较远的区域采用高压扰动注浆建造1号封堵体,将水砂淹没范围进一步缩小,然后在距离突水溃砂点较近的区域继续施工2号封堵体,对突水溃砂点周边进行治理;研发钻注一体化技术及钻具,能够避免钻孔在退钻后塌孔,影响后续注浆,实现钻探和注浆一体化作业。发明了孔口控压保浆装置,达到了在20 MPa注浆压力条件下浆液高效利用的目的;对巷道内松散砂体固结形成的封堵体采用取心和压水试验进行质量检验,取心完整,并且封堵体在1.8 MPa水压的作用下不漏水,说明封堵体质量良好。采用高压扰动注浆对掘进巷道内突水溃砂进行治理,具有安全、高效、经济等特点,并且可以有效避免治理期间二次灾害的发生。      

乌东德水电站大坝防渗帷幕成幕影响地质因素分析及处理措施

灌浆工程为地下隐蔽工程,其地质条件约束着实际的现场施工工艺,且不同地质条件对应不同的岩石属性,并将直接影响着防渗帷幕的优化设计,同时地质条件分析不足也将给整个灌浆工程带来很多不确定的风险。目前,地质条件预测在隧洞开挖过程中的研究较充分,但在灌浆工程中地质因素的研究较少。本文以乌东德水电站大坝防渗帷幕工程为例,分析了对防渗帷幕成幕有影响的岩溶、角砾岩、断层、岩层走向与帷幕走向大角度相交及长大结构面等地质因素,并针对不同地质因素的特点,提出了采取浓浆回填、灌浆孔加密加深、灌浆压力及浆材动态调整等处理措施,为帷幕灌浆工程优化提供了必要支持。