基于裂隙充填特征的坝基岩体灌浆效果评价

灌浆是水工建筑物基础处理中最常用的技术手段,通过灌浆封堵裂隙使基础岩体的防渗性、结构强度等达到设计要求。裂隙是透水透浆的最基本结构面,在灌浆处理中浆液对裂隙的充填程度是灌浆效果最直观的表现,由于灌浆工程的隐蔽性,裂隙的充填特征难以直接获取到,目前大多采用间接的压水试验法进行效果评价。利用钻孔摄像技术对灌浆钻孔进行成像探测,获取钻孔360°壁面图像,识别灌浆后的裂隙充填特征,考虑不同充填特征对灌浆效果的影响,建立以充填裂隙和未充填裂隙为要素的灌浆效果评价指标——钻孔内裂隙充填指数(borehole fracture filling integrity,BFFI),探讨BFFI与常规压水试验透水率结果的相关关系,利用三次多项式拟合两种评价指标的函数关系,建立基于钻孔内裂隙充填指数的灌浆效果评价标准,并将该方法应用到雅砻江桐子林水电站厂房坝区帷幕灌浆补充试验中,结果表明,(1)压水试验法和BFFI法的灌浆效果评价结果吻合度较高,进一步说明了BFFI法评价灌浆效果的可行性;(2)利用钻孔摄像技术开展灌浆效果评价,既直观地展示浆液在裂隙中的充填特征,又能反映灌浆效果,为灌浆效果评价提供了新的思路和方法。     

浅析风水联合钻孔裂隙冲洗法在官地水电站大坝帷幕灌浆中的应用

针对官地水电站大坝帷幕灌浆中坝基7#~10#坝段存在错动带、夹泥等薄弱地质情况,通过试验研究采用单一压水冲洗和风水联合冲洗法对钻孔裂隙进行冲洗,并根据后续的灌浆和压水检查来对比分析两种冲洗方式的灌注范围、注入量及浆液置换、充填裂隙的效果,确保冲洗后的灌浆质量满足设计要求,为以后类似工程地质条件的施工提供一定的参考。     

地质条件对隧道工程影响分析

通过采用浅层地震弹性波速度分析、孔内波速测试、钻孔数字测井和井下电视摄像，钻探工程以及钻孔围岩物理力学测试数据等方法，对隧道工程作了简要的概括。着重对隧道区特殊地质条件(地形地貌、地层岩性、地质构造、地震、水文地质条件、围岩物理力学指标及类别)进行了综合分析及合理划分，将大同煤田侏罗系含煤地层对隧道区产生的严重影响论述如下：①煤层采空区、开采面积、开采深度、煤柱比例、顶板垮落、地质构造、冒落带、裂隙所引起的地层稳定性。②褶皱带、断层、片麻岩风化带、节理、裂缝、岩石质量低等所引起的地层稳定性做了详细的、科学的论证与评价。最后对隧道区各段施工中出现的问题和采取的措施提出了建设性的建议如下：①对煤层冒落带或裂隙带应采取有效治理和防范措施。②对基岩风化带、岩体破碎应采取围岩加固措施。③对褶皱造成岩体破坏和破碎应采用导管注浆锚固等措施加固围岩。④对处于煤层火区内，隧道施工中会受到高温有害气体的危害，应进行钻孔帷幕灌注，密闭火区。⑤对煤层采空区瓦斯气体有可能沿裂隙、裂缝转移或富集应加强监测与防范。⑥对塌陷裂缝应进行分段支护。⑦对地表裂缝应进行灌浆或充填处理等。     

论帷幕注浆施工中的压力管理

在帷幕注浆施工中,注浆压力是一个重点控制的内容,通过注浆压力的分析、研究,可以判别浆液在岩石裂隙中充填、扩散、挤密过程,从而调节浆液浓度变化、控制注浆量,在很大程度上能控制帷幕注浆治水效果及经济成本。结合赵家湾铜矿帷幕灌浆治水工程,分析了帷幕注浆施工中浆液在岩石裂隙中充填、扩散、挤密过程注浆压力的变化规律,为注浆施工的压力控制提供依据。     

深矿钻孔帷幕灌浆的数值模拟与应用

深矿钻孔帷幕灌浆受到钻孔的垂直度、钻孔灌浆压力和扩散半径等因素的影响,使得灌浆的技术难度加大,直接影响帷幕的形态及防渗效果。采用基于UDEC离散单元程序的数值模拟方法,对深孔帷幕灌浆压力的扩散分布及浆液的流动扩散形态进行模拟,可以为深孔帷幕注浆工程设计和施工提供参考和指导。     

敏东一矿软岩区地下水注浆治理技术及应用研究

由于敏东一矿南一采区覆岩岩性较软且粘土成分含量较高,造成采空区垮落带的储水空间有限,煤矿面临的矿井水外排压力和地下水保护问题尤为突出。通过对导致地下水涌漏的原因进行分析,认为煤层开采引起的覆岩导水裂隙是造成地下水涌漏的主要根源,而采用地面钻孔、人工注浆封堵方法隔绝地下水泄流通道,实施帷幕注浆加固技术对巷道导水裂隙进行封堵,可以有效封堵覆岩导水裂隙。实践证明,根据矿区的地质和水文条件,按照隧道帷幕注浆工程设计和施工流程,优选注浆孔位置、间距、注浆材料和浆液配比、钻孔结构和注浆施工参数等,采用孔内止浆花管注浆对巷道软围岩进行帷幕灌浆,使巷道软围岩裂隙得到充分充填和加固,是解决矿区矿井水“零排放”难题、实现地下水保护的重要途径。     

水下隧道裂隙围岩渗流控制因素敏感性层次分析

在分析裂隙介质水力特性的基础上,采用层次分析法,结合工程实践经验,分析影响水下隧道裂隙围岩渗流控制的主要因素,并确定它们各自的权重。结果表明,每延米洞长洞室围岩断层等破碎带的平均宽度权重最大,是影响裂隙围岩渗流控制的最主要因素;其次为上覆含水体富水性和每延米洞长洞室围岩张开裂隙的平均数量。当洞室位置和洞室尺寸等参数设定后,每延米洞长洞室围岩断层等破碎带的平均宽度、上覆含水体富水性和每延米洞长洞室围岩张开裂隙的平均数量是影响水下隧道裂隙围岩渗流控制的最主要因素。研究结果可以为海底隧道及地下水封储油岩洞库等水下隧道的渗流控制及灾害防治提供科学的依据。     

大水灰比水泥浆-水玻璃速效灌浆堵漏

大水灰比水泥浆-水玻璃速效灌浆堵漏法，是我队通过帷幕灌浆之后，结合钻探施工中钻孔堵漏特点，将岩石基础灌浆法引用于岩心钻探钻孔护壁堵漏。通过某金矿区试验，效果很好。其优点是时间短，见效快，成功率高，材料消耗少。有效地避免了采用较大颗粒的惰性材料堵漏中，经常出现的一堵就返水，一钻又漏的情况，深受机台人员的欢迎。1．堵漏原理 主要是靠送入较大的水灰比（3∶1—0.5∶1）的水泥浆，在注浆泵的压力作用下，向钻孔裂隙中（漏失部位）压入。因浆液水灰比较大，水泥颗粒细小，易被挤进细小的裂隙中去，随着扩展面     

微生物灌浆加固裂隙岩体的渗流特性分析

裂隙岩体的防渗加固是影响工程稳定和安全的关键技术问题之一。在以往微生物加固砂土技术基础上,将微生物加固技术应用于裂隙岩体灌浆加固,研究结果表明,(1) 加固前围压对裂隙岩样的水力开度影响很大,加固后裂隙被碳酸钙沉积物充填,岩样的渗流由裂隙渗流转变为孔隙渗流,单位渗流量和渗透系数由围压和渗透水压共同控制;(2) 微生物灌浆加固后,不同围压和渗透水压力作用下裂隙岩样的单位时间渗流量减小了80.12%～90.04%,渗透系数可达到10–6 cm/s数量级;(3) 裂隙岩样灌浆加固过程中微生物诱导产生的CaCO3沉积物具有较好胶结作用,将劈裂岩样胶结为一个整体,达到了加固防渗效果。研究成果可为裂隙岩体的灌浆加固提供较好的参考。     

两江电站水库坝基帷幕灌浆施工工艺

两江电站水库坝基地质条件复杂,有多处断裂破碎带发育。在坝基处理过程中,采用流变性能好的水泥浆,通过合理的灌浆工艺,进行了钻孔帷幕灌浆施工,提高了坝基的承载力与防渗性能,取得了良好的施工效果。     

Treatment of the seepage problems at the Kalecik Dam (Turkey)

This paper describes the seepage prevention measures at Kalecik Dam. Water leaked from the foundation of the dam after the impoundment. The dam, 77 m in height, was constructed for irrigation purposes.

The foundation consists of Mesozoic ophiolite, Paleocene allochthonous units composed of different lithologies and Miocene conglomerate. Karstified and fractured Paleocene limestone outcrops on the right bank of the dam foundation. This unit extends into, and its thickness increases within, the right abutment. The leakage occurs towards the downstream springs through the right bank limestone.

The main grout curtain is 200 m long and 60 m deep and was constructed on the right bank. After reservoir impounding, new springs were observed in the downstream area. Therefore, after the construction of the dam, remedial curtain grouting was required and carried out in three stages. Firstly, the main grout curtain was supplemented by additional grouting to seal the fractures and infill karstic cavities. The diversion tunnel was also repaired. The curtain depth was the same as the depth of the previous curtain. The second stage of additional treatment consisted of new deep grouting. Some investigation holes were also drilled along the same alignment as the main curtain to locate the seepage in the region. These holes were extended to an elevation of 442 m. The final stage of grouting measures was between the spillway and the dam body and underneath the spillway.

As a result of the additional grouting measures, the spring discharges observed downstream of the dam embankment decreased. However, the seepage paths were extended and were moved with time so that the seepage problems are still continuing.     

贵州平寨水库左岸底层灌浆廊道大型充填溶洞及其形成机制

平寨水库坝址区以碳酸盐岩为主,岩溶较发育,水库左岸底层灌浆廊道大型充填溶洞,是水库地下工程施工开挖中揭露的规模最大、对水库渗漏影响最大、设计及施工处理难度最大的溶洞。本文以工程前期地质勘察工作为基础,在区域地貌、地质构造格局、地层岩性、地表及地下水系发育特征研究的基础上,结合工程防渗施工揭露的岩溶水文地质现象、洞穴充填物研究等,从可溶性岩层、地下水来源及运移途径、暗河冲刷与洞顶坍塌作用4个方面,对溶洞发育形成机制进行了研究。分析认为,鸡场背斜北西翼纵向张裂隙和横张裂隙及层间滑脱、断裂破碎带,为五里大洞鸡场洼地上坝洼地地下水向三岔河的径流提供了运移的原始空间与通道,形成溶洞的地下水为五里大洞鸡场洼地上坝洼地地下暗河,长期溶蚀作用使裂隙通道变为溶蚀宽缝并最终转化为岩溶管道,岩溶水沿此通道在左岸底层灌浆廊道桩号0+238～0+296m附近下中部岩体呈虹吸状循环,地下水的强烈冲刷与洞顶坍塌在溶洞形成过程中的作用巨大,后因深部径流条件改变,岩溶管道被逐渐堵塞,形成如今的大型充填溶洞。     

利用孔斜成像技术解译结晶岩体裂隙发育几何特征

钻孔电视成像技术由于其高精度数字记录成像的特点,克服了工程钻探过程中岩芯不连续、裂隙几何要素信息丢失等问题,在国内外工程勘察中得到了广泛的应用。但目前钻孔成像解译大都以竖直孔为主,倾斜孔成像解译应用较少。结合某地区地下水封洞库项目中的斜孔电视成像工作,介绍了斜孔成像裂隙的解译方法,通过空间坐标转换将结构面的视产状转换成真产状,并在此基础上针对该地区地下水幕系统和洞室所在位置深度范围内的裂隙发育情况分三部分对深部花岗岩结晶岩体裂隙几何要素进行了统计分析,揭示了相应的裂隙发育产状变化特征和垂向变化特征,结果表明该地区主要发育NE 20°~40°和NW 20°~40°优势构造成因裂隙,裂隙发育数量呈现先减小后逐渐增大并维持较稳定数量的变化趋势。以此可为评价洞库围岩稳定性、水幕系统水封效果等提供了可靠的数据支持。     

Seepage problems in the right abutment of the Shahid Abbaspour dam, southern Iran

In this study, seepage phenomena through the right abutment of Shahid Abbaspour dam are investigated. The Shahid Abbaspour dam is a 200 m high arch dam, which regulates the waters of the Karun River, serves power generation, and flood control and irrigation needs. The dam site lies in the Zagros Mountains of southern Iran. This region presents continuous series of mainly of karstic limestone, marl, shale and gypsum ranging in age from Jurassic to Pliocene. The region has subsequently been folded and faulted. Seepage from the Shahid Abbaspour reservoir occurs mainly through the karstic limestone.The basic foundation treatment of the dam consisted of consolidation grouting, a high-pressure grout curtain and a drainage curtain. Moreover, a 144 m high and 30 m wide concrete cutoff wall was built to prevent reservoir seepage through a clay-filled fracture zone in the right abutment. The grout curtain penetrates the “Principal Vuggy Zone” only beneath the central portion of the dam and below the cutoff wall. In the right abutment fan curtains were constructed to reduce drainage flows, but the seepage problem could not be solved. In order to determine the seepage direction and karstification pattern, hydrogeological studies have been carried out. Additional investigation boreholes have been drilled to monitor fluctuations in groundwater level. Besides these, water chemistry, dye tracer, pinhole and XRF tests have been carried out. As a result of these studies, seepage paths have been identified in the karstic limestone in the right abutment of the dam.     

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。      

“双液注浆法”在基坑堵漏中的应用研究

双液注浆法是在止水帷幕的渗漏处钻孔,找到基坑止水帷幕的渗漏通道,把一定浓度的水玻璃溶液及水泥浆溶液的混合液注入渗漏通道中,水玻璃与水泥浆的混合液快速凝结、迅速封住渗漏通道,起到隔水的作用.其施工步骤为成孔→找渗漏通道→双液注浆→巩固.文章还列举了天津地区采用双液注浆法处理基坑渗漏的两则案例.     

Contribution of spectral coherency analysis and tracer test to study leakage at the Doosti Dam reservoir,Iran and Turkmenistan

The Doosti Dam was built across the Harirood River on the border between Turkmenistan and Iran. During the reservoir impounding, leakage occurred as new springs through the sandstone layers of the Pesteleigh Aquifer and limy sandstone and limestone layers of the Neyzar–Kalat Aquifer, at the right abutment of the dam. To evaluate the grout curtain operation, a tracer test was carried out by injection of Uranine in a borehole located at the upstream of grout curtain in the Pesteleigh Aquifer. Tracer test results demonstrated a diffuse flow component through the grout curtain in the Pesteleigh Aquifer, but no tracer was detected at the main leakage point, SP1 Spring, emerged downstream of grout curtain from the Neyzar–Kalat Aquifer. Using the spectral coherency function, the lag time between changes in the water level of the injection borehole and water level in the tracer detected boreholes or discharge of the tracer detected springs was determined. Linear regression analyses indicated that the estimated lag time by the time series analysis was close to the first arrival time of the tracer. Therefore, the estimated velocities based on the lag time of time series could be considered close to the calculated velocities based on the first arrival time of the tracer. The estimated groundwater velocities based on the time series analysis ranged from 3.91 to 20.31 m h^?1, showed that diffuse flow dominated pathways from the reservoir toward the downstream boreholes in the Neyzar–Kalat Aquifer, while conduit flow was present within the pathways toward the SP1 Spring. Regarding the reservoir volume, the negligible amount of leakage at the maximum water level of the reservoir confirmed well overall operation of the grout curtain at the dam site.     

松软地层防渗灌浆帷幕结构性状实验研究

松软地层透水率较大,防渗灌浆工程吃浆量相对较大,浆液扩散极不规则,形成的防渗帷幕,包括防渗幕体厚度、力学性能、防渗效果等结构性状难以准确把握,现有的方法和技术主要采用压水试验、标贯、钻孔取心、物探等方法获取相关信息,但带有极大的不确定性,直接影响到防渗质量的评价。在现场进行多工况灌浆原型试验研究,通过注水试验、孔斜测定、取心测试、全断面开挖等多种方法,真实呈现防渗幕体的性状,包括幕体有效厚度及其影响范围、幕体强度性能和渗透性能。结果表明,在松软地层采用浆体封闭、脉动灌浆控制灌浆工艺,孔距1.5m,两排排距0.8m,并采用适宜的灌浆控制参数灌注可控性黏土水泥浆材,简便高效,孔周挤密区、结石体及胶结体形成的有效幕体均一性好,防渗效果达到5lu以下,灌后28d结石体强度达到3MPa以上。灌浆工艺和参数可直接供类似地层应用。对于不同类型地层在不同灌浆材料、灌浆工艺、灌浆参数情形下的灌浆结构性状,有必要研发物理模型进行大样本室内试验研究。     

油页岩原位开采区注浆封闭浆液优化及其防渗效果实验

为提高油页岩原位转化加热效率、减少油气污染,采用注浆技术对油页岩开采区进行封闭止水。基于扶余油页岩开采区地质条件,对优化封闭浆液配方与封闭效果进行实验研究。首先基于正交试验,获得了不同指标下的优化配方,进而通过综合分析法,选出符合此封闭区要求的优化配方;为了验证优化浆液的封闭效果,对比分析了浆液充填前后油页岩试样渗透率的变化。结果表明：浆液优化配方为水灰质量比0.85,w（钠基膨润土）4.0%、w（微硅粉）6.0%、w（聚羧酸减水剂）0.5%;当围压为扶余油页岩开采区地应力时,充填浆液试样的渗透率均约为0.1×10^-3 μm²,远低于未充填的试样,优化浆液封堵试样裂缝效果较好。