万福煤矿深部水压致裂地应力测量

为了克服煤田上覆冲击层厚度高达700m所造成的困难，保证超千米深部地应力测量的成功，对传统水压致裂法测量方法和设备进行改进，增加测量系统的耐压能力和测试系统的精度。在完成的7个钻孔、37个测点的现场实测中，6个钻孔的深度接近和超过1100m，最大测点深度为1105m，创造了我国水压致裂法测量地应力钻孔深度的新记录。通过实测，确定了矿区的地应力状态及其分布规律。研究结果表明，37个测点的最大水平主应力与垂直主应力的比值为1．441～3．224，平均为1．97，反映了矿区地应力场以水平应力为主导的特点。测量结果可为矿山建设和开采设计提供科学的依据。     

北京地铁10号线国贸—双井区间土压平衡 盾构施工数值模拟研究

 以北京地铁10号线国贸—双井区间盾构施工为背景,运用FLAC3D软件对盾构过程进行动态模拟,在模拟盾构隧道周围设置应力及位移监测点,计算得出隧道周围土体垂直和水平方向位移及相应的应力变化规律。研究结果表明：盾构推进过程中,盾构开挖面前方土体受到挤压作用,不仅表现在竖向位移,水平位移也有同样现象发生,水平位移绝对值不如竖向位移显著;在盾构开挖面附近边界,土体垂直和水平应力下降明显,释放率在50%左右;盾构推进对周围土体的剧烈扰动主要集中在开挖面处至开挖面后方20 m土体范围内。数值模拟结果跟实测结果吻合较好。     

润扬大桥锚碇基岩摩阻力试验研究

采用室内试验和现场剪切试验等手段研究了润扬大桥南北锚碇基底基岩-混凝土胶结面的强度，并根据试验研究成果及现场实际情况，综合分析多种影响因素，研究确定整个锚碇范围内基底摩阻力情况。     

徐州矿区深部地应力测量及区域构造作用分析

为了指导徐州矿区深部巷道维护及开采安全,在5个埋深超过800 m的深井采用空心包体三维应力解除法进行了原岩地应力测量。实测数据表明：所有测点的最大水平主应力均略大于垂直主应力,方向呈NW-SE向, 近水平方向;由于受区域地质构造作用,地应力存在东西差异,西部和西北部矿井,近似呈静水压力型,东部矿井水平应力是垂向应力的1.19～1.23倍;分析了深井地应力量级、主应力与侧向系数随深度的分布规律;分析了区域郯—庐大断裂左旋平移的基础上形成的北东向徐—宿弧形推覆构造作用影响,确立了矿区实测地应力场与区域地质构造的一致性关系,为深部开采提供可靠的地应力基础数据。     

Advance of in-situ stress measurement in China

In-situ stress is an essential parameter for design and construction of most engineering projects that involve excavation in rocks.Progress in in-situ stress measurement from the 1950s in China is briefly introduced.Stress relief by overcoring technique and hydraulic fracturing technique are the two main techniques for in-situ stress measurement in China at present.To make them suitable for application at great depth and to increase their measuring reliability and accuracy,a series of techniques have been d...     

煤矿深部岩体地应力特征及开挖扰动后围岩塑性区变化规律

 基于淮南5个煤矿区的水压致裂法地应力测量结果,揭示淮南煤矿区的地应力特征及其随岩性的变化规律,分析开挖后围岩应力特征及塑性区变化规律,初步得出如下结论：(1) 淮南5个煤矿区地应力以构造应力场为主,属高应力区;(2) 岩性对岩体地应力侧压系数影响大,砂岩区岩体地应力侧压系数为1.52～1.87,泥岩区岩体地应力侧压系数为1.08～1.18;(3) 岩性是影响围岩塑性区特征的重要因素。由于岩性的差异,最大主应力相近的潘一煤矿和顾桥煤矿南区围岩塑性区范围有较大差异。与此同时,刘庄煤矿实测部位最大水平主应力小于潘一煤矿,但由于矿区测试部位的岩性为灰泥岩,围岩塑性区范围明显大于岩性为石英砂岩的潘一煤矿。研究结果可为类似巷道围岩的变形破坏机制分析以及巷道加固支护提供参考。     

深部岩盐矿地应力的确定及特征分析

针对深部岩盐矿溶腔稳定性分析及地应力场分析的要求和深部岩盐矿钻孔水溶开采的条件，结合长山岩盐矿深部地应力研究的实际情况，确定了矿区地应力测试方法、地应力测点和试样选择的一些要求：按照声发射Kaiser效应测地应力的基本原理，提出了沉积岩层非定向钻孔岩芯坐标方向建立的方法和多方向取样及地应力椭球回归分析的声发射Kaiser效应地应力测试方法。该方法根据三维空间多方向试样的Kaiser效应实验结果，采用多元非线性拟合方法确定测点地应力椭球的一般方法，再由二次正交变换确定测点地应力椭球的标准方程，以求得地应力的大小和方向。此方法能避免实验误差的较大影响。长山岩盐矿实验矿井深部地应力测试结果及分析表明，长山岩盐矿深部存在水平构造应力，最大主应力方向在离地表800m深左右由水平方向转为垂直方向；距离地表1000m左右深的岩盐层中，最大主应力一般为30MPa左右。     

岩石破坏声发射平静期及其分形特征研究

 通过岩石加载的室内试验方法,测试不同岩石破裂全过程的力学特征及其声发射特性,得到岩石破坏全过程力学特性——岩石的全应力–应变曲线、声发射事件累积数、声发射事件率等相关曲线及参数,给出声发射事件数、事件率与应力水平、时间之间的关系。着重讨论一次性加载过程中塑性变形阶段明显的岩石在加载接近峰值强度时单位时间内的应力增长速度减小,也即这一阶段出现明显的“耗时”现象;并且在此阶段监测到的声发射事件率出现明显下降,出现声发射相对平静阶段;而对于塑性变形阶段不明显的岩石来说,这一阶段则基本不存在明显的“耗时”现象,声发射的监测中也没有发现声发射相对平静期现象。另外,还运用分形理论,研究分析处于不同加载应力比的岩样在各个阶段的声发射分形维数,特别是研究声发射平静期维数变化情况。指出在加载初期分形维数处于较低值,且分形维数随加载应力增加而逐步增加;在加载到峰值应力的40%左右时,分形维数开始下降;在加载接近到峰值应力时,即处于声发射平静期阶段时分形维数逐步降到最低,且此时预示着岩石的破坏。此外,结合室内试验,还对现场岩体失稳破坏声发射监测中的一些实际问题进行总结和分析,为更好地应用声发射手段进行岩体稳定性现场监测预报提供理论依据、方法和手段。     

赵楼煤矿1 000 m深孔水压致裂地应力测量及其应力场研究

 赵楼煤矿是目前国内开采最深的非金属矿山之一,处于曹县-郓城活动断裂带上,区内地质构造较为复杂。为了掌握矿区原岩应力场分布规律,应用深孔水压致裂地应力测量技术开展地应力测量工作,获得该矿区2个钻孔中16个测段的应力状态。测量结果表明：矿区最大主应力随深度增加基本呈线性增大,且在800 m深度处应力值有所变化,最大水平主应力为28.45～45.75 MPa,方向NEE,反映出矿区地应力场以水平应力为主导的特点,测量结果可为矿山建设和开采设计提供科学依据。     

利用地应力测量技术探查油井地层注水分布特征

对油层所在层段进行压裂注水驱油可以提高油田采收率,而确定注水的流向是合理部署注采井网的重要依据。利用电磁波地应力测量新技术对周庄G1井地层注水空间分布特征进行探查,并将探测得到的电压值换算成地应力值,研究表明,地应力值的大小与富水程度具有一定的相关性,低地应力值对应于强富水,高地应力为弱富水或不富水。从注水层段地应力纵向和平面分布及含水层厚度3个方面分析注水影响范围及富水性平面分布特征。探测结果显示：在G1井东部40 m及SW50 m处存在2个近南北向地应力低值条带,为注水后富水的区域,其后的采油实际资料证实了探测结果的可靠性,为油井旧井挖潜的有效技术手段。     

Investigation of hydraulic parameters of a weathered mylonite fault from field pumping tests: A case study

This paper presents a case history where the hydraulic parameters of a weathered mylonite fault located in the way of shield tunneling for the Xie-Zhong section on Metro Line No. 7 in Guangzhou City were determined using a series of field pumping tests. The weathered mylonite fault contains fissure groundwater, which would result in a high potential of water ingress during shield tunneling within the weathered mylonite strata. Therefore, the first stage of pumping tests involving five pumping wells was initially carried out. To verify the validity of the hydraulic parameters derived, the second stage of pumping tests involving four pumping wells was carried out. In addition, both an analytical method that involves a well-flow calculation for a fissure-confined aquifer for non-orthogonal anisotropic rock mass and a numerical simulation based on the theory of the equivalent continuum porous media were used to derive the hydraulic parameters based on the field pumping test data. The analytical method can provide the values of hydraulic conductivity only in the horizontal plane and is not able to capture the hydraulic characteristics of standalone stratum of the multi-aquifer system. In the numerical model, the weathered mylonite fault due to the nature of non-uniform mylonite strata distribution is further divided into four sub-regions with different hydraulic conductivities, according to the calculated influence radius of groundwater drawdown or geological formation. This leads to estimates of hydraulic parameters that are closer to real values, and enhances our understanding of non-uniform fissure development.     

Measurement of in-situ stress in weak rocks at Mont Terri Rock Laboratory, Switzerland

In-situ stress measurements in weak rocks, such as clay shales, that respond strongly to environmental changes are particularly difficult. An extensive in-situ stress measurement program has been conducted at the Mont Terri Rock Laboratory in Northwestern Switzerland. Hydraulic fracturing, Undercoring around a 600-mm-diameter borehole using CSIRO triaxial strain cells and the Borehole Slotter were used to establish the state of stress for the Opalinus Clay at this location. Conflicting orientations and magnitudes resulted from the measurement programs. Three dimensional elastic modelling was used in conjunction with tunnel and borehole observations to establish the most likely stress tensor. A stress measurement program using a borehole deformation gauge is currently underway to check the stress tensor resulting from the observational modelling.     

岩石的风化损伤属性与缩小防护煤柱开采机制研究

以大量试验数据、现场测试资料和大规模缩小防护煤柱开采工程实践为依据,研究隐伏煤田基岩风化带的分布特点。结果表明:岩石风化损伤后具有强度降低,塑变能力增强;多趋泥化,裂隙易于弥合,再生隔水能力显著增强,亲水能力强等变异特征以及工程地质特性。重点论述风化带内煤层开采具有移动快、变形大、回缩快和下沉大等覆岩破坏移动演化新特征,获得以泥质岩类为主的风化带岩层受开采扰动的影响,具有阻隔底含水下渗和抑制导水裂隙带继续发展的双重作用和煤岩柱厚度与风化程度是影响导水裂隙带发育高度的主导因素等新的认识。同时,阐述了缩小防护煤柱开采的机制,系统地提出了采空区滞后控水、煤水分流、加大开采高度、物探预测和地质弱面预先加固等一系列确保安全的关键技术保障措施。对类似矿井浅部资源的回收与安全开采具有理论意义和应用价值。     

川西北跨度23 a的原地应力实测数据特征及其地壳动力学意义分析

 研究区位于龙门山断裂带北段的中央断裂带和前山断裂带之间,该区地质结构主要为准原地体系和逆冲推覆体系,岩性以志留系下统的泥岩、粉砂泥岩分布最广,遍及全区。为了满足该区一工程建设的需要,在研究范围内开展了4个钻孔的水压致裂原地应力测量工作,测试时间跨度达23 a。测试数据显示,虽然测试时间跨度达23 a,但是原地应力状态基本没有变化,研究区最大水平主应力方向的优势方向为N24.4°W,最大、最小水平主应力随深度线性增加的梯度分别为0.036和0.025。基于实测数据计算的特征参数kH max,kh min,?m和R在23 a内没有变化。该区域位于龙门山断裂带中央断裂的下盘,为被动盘,断层活动性和地震活动性都极其微弱,这种特殊的区域地壳动力学条件决定了研究区稳定的区域应力场特征。通过与以往研究成果的对比分析可知,?m较好地反映了该区域地壳的应力积累能力,即从应力积累的角度反映了区域断层的强度,这一研究与以往研究成果十分吻合。在未来的研究中,或许可以利用实测应力资料计算的?m值,再结合区域断层和地震活动性的比较分析来评价特定区域的地震危险性。     

Grouting a tunnel cave-in from the surface: a case study on Kurtkulağı irrigation tunnel,Turkey

This paper describes the treatment of tunneling problems at Kurtkulağı irrigation tunnel, particularly focusing on the Kurtkulağı tunnel which is 1255 m in length and 3.50 m in diameter, is an important of the Yumurtalık Plain Irrigation Project. The tunnel was excavated using conventional dull and blast, but during the tunneling problems occurred. Within a 70 m long section of the tunnel, cave-in occurred at two locations both along the fault zone in tunnel alignment. Slope stability problems were experienced too at inlet and outlet section of the tunnel. A sinkhole was formed at the surface as a result of the cave-in. There are an Allocthonous Cretaceous complex sequence and Miocene sandstone–claystone units, which have a faulty contact in the tunnel alignment area. The complex sequence consists of mainly weathered andesite, spilitic agglomerate, radiolarite, serpentinite and limestone blocks. The claystone to sandstone is thin-medium bedded and has medium-weak rock substance properties. The fault zone with an approximate width of 150 m and consisting of extremely weak crushed rocks crosses the tunnel alignment at mid-section. Some treatment methods were applied to remedy this collapse. Cut and cover method was applied for the first 955 m of the tunnel inlet due to the shallow overburden and very weak rock properties. However, cave-ins delayed the tunnel construction for 1 year and increased the cost by 9%.     

Stress ratio effect on fatigue life of tropically weathered rock

This paper investigates the fatigue life of weathered granite and weathered sandstone using a stress ratio of R = 0.17. A small stress ratio is adopted to control data discrepancy between weathered rocks for which stress amplitude is known to affect the fatigue life. The range of varying static strength between weathered rocks, especially for highly weathered rock (grade IV) which has lower static strength, resulted in adopting this small stress ratio. The details of rocks tested, including microscopic petrographic characterization as well as their physical properties obtained from laboratory work, is also explained in this paper. Weathered rock specimens from slightly weathered to highly weathered (grade II, grade III and grade IV) granite and sandstone were used during the investigation. The specimens were representative of rock collected in Sungai Buloh (granite) and Puncak Perdana (sandstone) in Selangor, Malaysia. In order to eliminate the influence of frequency and waveform, all rock specimens (54 in total) were tested under a cyclic compression load with a frequency of 1 Hz using a constant sinusoidal waveform. Result shows that grade IV specimens are the least affected by the small cyclic stress ratio as compared to grade II and grade III specimens. The number of cycles to failure is not dependent on rock weathering grade; it is greatly related to the petrological and microstructure of the individual rock. However, the weathering degree of a rock does contribute to the weakening of the rock's structure, consequently affecting the life of the rock.     

可用于确定水平地应力分量和围岩弹性模量的TBA位移反分析法

地应力、围岩弹性模量等参数的测定是岩石力学和工程地质学的重要研究课题之一。虽然已有许多有效的测定方法，但并非都能满足工程设计的要求。因此，一种有别于传统地应力量测方法的TBA位移反分析法被提出，并对相应的基本原理和方法进行讨论。为说明TBA法的实用性，给出了在“引大入秦”和三峡船闸边坡等工程中的应用实例。     

基于岩碴粒径分布规律的TBM破岩效率分析

岩碴的形状、大小及其粒径分布规律是综合反映TBM破岩效率的重要指标,也是TBM掘进参数与岩石性质的重要联系。根据盘形滚刀破岩机制,对TBM掘进岩碴进行了现场量测和筛分试验,获得了TBM岩碴尺寸特征和粒径分布规律。在此基础上,对实测岩碴尺寸和粒径分布数据进行了统计分析和理论分布函数拟合。分析了粗糙度指数与岩石强度、岩石耐磨性的关系,探讨了不同围岩等级下粗糙度指数随掘进推力的变化规律。研究结果表明:①片状岩碴的长轴与短轴之比约为1.5,而长轴与厚度之比则差别较大,其长轴、短轴和厚度均服从正态分布;②不同岩性条件下岩碴粒径分布均符合Rosin–Rammler函数分布;③岩碴粗糙度指数越大,TBM破岩效率越高;硬岩条件下岩碴粗糙度指数随单轴饱和抗压强度增大而减小,而中硬—软岩条件下则相反;④无论是软岩还是硬岩,岩碴粗糙度指数随岩石耐磨性增大而减小,岩石耐磨性越强,TBM破岩效率越低;⑤TBM破岩效率与围岩等级密切相关,可根据现场实测岩碴粒径分布规律,确定Ⅱ级和Ⅲ级围岩条件下TBM破岩效率最佳时的掘进推力区间。     

厦门翔安海底隧道风化槽围岩渗透破坏及岩体流变试验研究

厦门翔安海底隧道需穿越多处海底风化槽,该地段围岩为破碎、风化的花岗岩,渗透性强、水压高、自稳性差、施工风险大,其物理力学特性研究对设计和施工方案制定意义重大。本文对风化槽围岩的渗透破坏和流变试验进行研究。渗透稳定性评价结果表明,在全水头作用下,F1、F4风化槽强风化带岩体渗透稳定性较好,但隧道开挖将引起地层变形,围岩渗透稳定性改变,施工中需进行评估监测并采取必要措施。三轴试验结果表明,风化槽强风化花岗岩强度低、变形大、弹性模量低,在应力达到峰值后,有明显的塑性流动。三轴流变试验结果表明,风化槽强风化花岗岩变形具有明显的粘性时效特征,对围岩开挖后的掌子面稳定性和长期变形稳定性都不利,在设计和施工中应引起注意;采用非线性蠕变模型对其流变特性进行拟合,效果良好,由此建立相应的流变力学模型。研究成果为本工程风化槽围岩注浆加固和支护结构设计提供可靠依据。     

玲珑金矿深部地应力测量及矿区地应力场分布规律

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