共查询到20条相似文献，搜索用时 46 毫秒
1.
Sung-Soo Cha Jin-Yong Lee Dae-Hyuck Lee Eric Amantini Kang-Kun Lee 《Engineering Geology》2006,84(3-4):229-243
Feasibility of storing LNG in a lined rock cavern was evaluated using a pilot cryogenic rock cavern constructed in Daejeon, Korea. The pilot program included hydrogeological and engineering characterization of the rock mass around the cavern, design and construction of a drainage system, and pilot operation of the cryogenic cavern. An appropriate drainage system is most important to protect the containment system of LNG from thermal shocks due to ice lenses and hydrostatic pressure of groundwater. As a part of the pilot program, this study focused on the evaluation of hydraulic and engineering properties of the rock mass around the cavern. For this purpose, engineering logging of the rock cores, single and cross-hole hydraulic tests, and recharge/drainage tests were performed using seven drilled holes with different trends and plunges. Three main joint sets were found from the logging of the rock cores, acoustic borehole televiewer, and window mapping. The orientations of the three major joint sets were 60/209, 40/171, and 29/331, which can provide the main groundwater flow paths. Mean RQD values ranged from 56 to 88, which were classified as fair and good, although varying with depth along single boreholes. Hydraulic conductivity from the single and cross-hole hydraulic tests estimated in the order of 10−6 or 10−7 m/s and corresponding transmissivity ranged between 10−5 and 10−6 m2/s. Permeable intervals identified from the hydraulic tests were mostly located above the cavern roof. Below the roof, the permeable zone was difficult to observe. According to the hydraulic communication tests performed for some designated intervals, hydraulic connection between boreholes was highly varied with depth or location, which indicated a very different distribution of water conducting joint sets along the boreholes. When water was injected at R1 with constant or varying flow rates, monotonous and stable seepage was observed at observation boreholes. From this, some stable drainage was expected even in relatively heavy rainfalls. When designing the drainage system of the cavern, the drainage holes should be orientated to maximize frequency of encountering the major joint sets and the permeable intervals identified from this study. 相似文献
2.
3.
Sung-Soo Cha Kang-Kun Lee Gwang-Ok Bae Dae-Hyuck Lee Nicolas Gatelier 《Engineering Geology》2007,93(3-4):117-129
Hydrogeological monitoring was conducted around a pilot cavern for underground cryogenic LNG (Liquefied Natural Gas) storage. The monitoring was mainly focused on the operation of a drainage and recharge system. After the operation of the drainage system commenced, the drainage rate decreased rapidly in the initial stages and then decreased gradually. Hydrogeological monitoring revealed that the rock drainage system operated effectively. During drainage, the water table was maintained below the cavern roof. The recharge for ice-ring formation was performed in two phases. The first phase involved the cessation of pumping in downward-drainage holes and the second involved the closure of upward boreholes. Since the water table was maintained below the cavern roof, artificial recharge was planned at first. However, it was not implemented due to heavy rainfall in the recharge stage. On the basis of hydrogeological monitoring and hydraulic tests, it was found that the fractures above the roof and on the right wall of the pilot cavern mainly affected seepage into the cavern and thermal variation due to the storage of liquid nitrogen. Thermal variation was examined by the thermometers installed around the pilot cavern. The cooling and thawing processes reveal the characteristics of thermal distribution in the rock and the 0 °C isotherm. The cooling phase lasted for six months, and the 0 °C isotherm progressed in time after the injection of liquid nitrogen into the cavern. The isotherm propagated up to about 4 m from the floor and the sidewall of the cavern and about 3 m from the cavern roof. The cooling rate of the rock mass above the cavern roof was lower than that of the other cavern sides due to the gaseous space in the upper part of the containment. The fractures were analyzed and considered for thermal modeling. A two-dimensional finite element analysis was performed to compare the field monitoring at the pilot cavern. The numerical modeling shows the distance between the ice ring and heat transfer pattern of the fractures around the pilot cavern. The propagation of the measured and calculated 0 °C isotherm reveals that the water-conveying joint on the right wall might affect thermal propagation through a thermal pipe. 相似文献
4.
5.
Sophie Messerklinger 《Geotechnical and Geological Engineering》2012,30(6):1421-1433
The Plavinas run-off river scheme in Latvia is founded on fine-grained deposits with artesian aquifers. These aquifers are drained with free flowing wells to assure the stability of the structures. In March 1979, one of these wells suddenly discharged high amounts of solids together with the drainage water. After a few days the water discharge stopped, the artesian pressures in the foundation increased and dirty water flew from the bottom of the tailrace channel area. Foundation failure could be mitigated by turning piezometers into free flowing relief wells. However, it was a critical situation for the powerhouse and caused significant permanent displacements of the concrete structures. A root-cause analysis was performed which is presented in this paper. It was found that caverns at the interface of alluvial and fine-grained deposits formed due to erosion of the fine fractions of the alluvium through the drainage wells. Such a cavern collapsed which caused the well blowout and the plugging of the drainage well resulting in increasing pore water pressures and local liquefaction of the powerhouse foundation. 相似文献
6.
Mechanical responses induced by temperature and air pressure significantly affect the stability and durability of underground compressed air energy storage (CAES) in a lined rock cavern. An analytical solution for evaluating such responses is, thus, proposed in this paper. The lined cavern of interest consists of three layers, namely, a sealing layer, a concrete lining and the host rock. Governing equations for cavern temperature and air pressure, which involve heat transfer between the air and surrounding layers, are established first. Then, Laplace transform and superposition principle are applied to obtain the temperature around the lined cavern and the air pressure during the operational period. Afterwards, a thermo-elastic axisymmetrical model is used to analytically determine the stress and displacement variations induced by temperature and air pressure. The developments of temperature, displacement and stress during a typical operational cycle are discussed on the basis of the proposed approach. The approach is subsequently verified with a coupled compressed air and thermo-mechanical numerical simulation and by a previous study on temperature. Finally, the influence of temperature on total stress and displacement and the impact of the heat transfer coefficient are discussed. This paper shows that the temperature sharply fluctuates only on the sealing layer and the concrete lining. The resulting tensile hoop stresses on the sealing layer and concrete lining are considerably large in comparison with the initial air pressure. Moreover, temperature has a non-negligible effect on the lined cavern for underground compressed air storage. Meanwhile, temperature has a greater effect on hoop and longitudinal stress than on radial stress and displacement. In addition, the heat transfer coefficient affects the cavern stress to a higher degree than the displacement. 相似文献
7.
软土在低水力坡降下的渗流会偏离达西定律,即为非达西渗流模式。假设孔隙水渗透服从指数渗流模式,采用镜像法原理推导了浅埋单孔和双孔圆形隧道非达西渗流场的解析解。结合算例,对浅埋圆形隧道非达西渗流解析解与达西渗流解析解进行了对比分析与验证,并对非达西渗流指数、隧道周围土体与衬砌渗流系数比值对隧道渗流场的影响进行了讨论。结果表明：非达西渗流指数、渗流系数比值对隧道渗流量和周围土体孔压均有较大的影响;随着渗流指数逐渐增大,土体内水头损失加快,隧道周围土体孔压及渗流量逐渐减小;随着土体与衬砌渗流系数比值逐渐增大,衬砌排水能力增强,隧道渗流量逐渐增大,隧道周围土体孔压减小更大。 相似文献
8.
Dynamic response and pore pressure model of the saturated soft clay around the tunnel under vibration loading of Shanghai subway 总被引：2，自引：0，他引：2
This paper studies the saturated soft clay around the tunnel between Jingansi Station and Jiangsu Station of Shanghai subway line No.2. The continuous dynamic monitoring is conducted by means of embedded earth pressure piezometers and pore piezometers around the tunnel. The response frequency and stress amplitude of the saturated soft clay are studied with the distance from the tunnel due to the subway vibration loading. A formula is proposed for the attenuation of the dynamic pressure response in the soil. Then, based on the continuous field monitored data, and using the laboratory GDS (Global Digital System) test apparatus, the developing law of the pore water pressure of the saturated soft clay around tunnel is explored with the distance. By the GDS test, the model of the increasing pore water pressure of the saturated soft clay is put forward under the vibration loading. It is also amended by field monitored data. Finally the model is obtained. The result offers a valuable reference to the design, construction and the safe operation of the subway tunnel. 相似文献
9.
The compressed air energy storage(CAES) is a much-awaited new system for load leveling power supply. An economical system must be developed, preventing leakage of stored air (with pressures of more than 20 atm) using groundwater pressure surrounding an unlined cavern in hard rock. The air tightness of the rock around the cavern must be confirmed. In this study, the hydrogeology of the test site was examined prior to field air tightness tests in the borehole. The results indicate that, when evaluating the hydrogeology of the test site related to the air tightness of rocks, it is necessary to understand the geological structure and fracture characteristics of the site. This is done by means of a field survey, investigations and tests in and between the boreholes, and the examination of the distribution of permeability and pore water pressures. 相似文献
10.
Ming Lu 《Engineering Geology》1998,49(3-4):353-361
A three-dimensional finite element analysis was performed to simulate field tests at a pilot gas storage project. The storage was a shallow rock cavern lined with a 6 mm thick steel liner. During the tests, high internal pressure up to 52 MPa was applied and deformation of both rock mass and the steel liner was recorded. The maximum rock displacements of less than 6 mm was numerically predicted and fits the measurement very well. The three-dimensional nonlinear finite element modeling has confirmed the overall stability of the structure and revealed the functioning of each structural component, including the rock mass, concrete lining and the steel liner. 相似文献
11.
12.
An experimental investigation was carried out on the reconstituted Tunis soft soil (TSS) that was extracted from the centre of Tunis City at 35-m depth. Three series of consolidation tests were performed on TSS specimens. The first series included consolidation tests by preload. In the second series, vacuum consolidation tests were performed. The third series comprised a vacuum consolidation test combined with the preload. Excess pore water pressure and settlement were measured during the consolidation tests. Experimental results showed that for the same magnitude of preload and the vacuum pressure of 4, 8, 16 and 30 kPa, the settlement caused by the vacuum pressure is lower than that generated by the preload, while the settlements generated by preloads of 60 and 100 kPa are slightly lower than those caused by vacuum pressure of 60 and 100 kPa. A rapid dissipation of recorded excess pore water pressure around the geodrain was observed compared to that measured close to the cell border. 相似文献
13.
真空预压法加固吹填土的孔隙水压力试验研究 总被引：2，自引：0，他引：2
利用真空预压法处理吹填土时,孔隙水压力变化常常反映土体固结程度的好坏。通过6个模型箱试验,监测不同排水系统下孔隙水压力变化,确定有效排水体间距。研究发现0.4m间距的土内孔压下降效果比0.8m间距的土内孔压下降效果好;排水体内的孔隙水压力与排水体类型有关,且距离排水体10 cm处土体内的孔隙水压力仅为排水体内孔隙水压力的1/2弱;滤膜排水系统中的吹填土孔隙水压力下降幅度最快,B型排水板系统次之,而砂井系统最慢。另外,对于吹填土而言,排水体有效间距介于0.4m与0.8m之间,其中滤膜的有效间距最大,B型排水板次之,砂井远小于前两者。 相似文献
14.
基于反映裂隙岩体渗透张量各向异性特性的广义达西定律与相对透水率等裂隙岩体渗流基本理论,应用三维非线性有限元方法,对长江三峡工程永久船闸高陡边坡在连续降雨条件下裂隙岩体饱和-非饱和、非恒定渗流扩散过程进行了三维数值仿真分析,得出了连续降雨条件下船闸高陡边坡裂隙岩体渗流场的时空分布规律及典型降雨时段闸室混凝土衬砌上的最不利外水压力荷载,对暴雨入渗情况下闸室边墙稳定性与安全性进行了评价。分析结果表明,闸室混凝土衬砌具有较高的安全度;船闸高陡边坡内排水系统效果显著,即使遭遇长期强降雨,闸室衬砌上的外水压力荷载受降雨的影响也不大。 相似文献
15.
隧道斜交穿越地裂缝的模型试验研究 总被引：1，自引：0，他引：1
西安地区由北向南间隔分布有十多条近东西走向的地裂缝,建设中的多条地铁线路与地裂缝呈斜交状态。为了揭示地铁隧道斜交穿越地裂缝时受地裂缝活动而产生的力学性状变化,采用50:1几何相似比尺的物理模型试验仪,在合理模拟围岩地层、衬砌结构、应力条件、地裂缝与洞轴线交角及其错动位移基础上,开展了斜交地裂缝活动条件下隧道衬砌结构与围岩相互作用的物理模型试验研究,并与正交地裂缝活动下的测试结果进行了对比分析。表明斜交地裂缝活动对地铁隧道的影响范围更大,各变形缝均有明显的沉降差发展;邻近斜交地裂缝的衬砌结构易处于“悬臂梁”受力状态,衬砌结构不均匀沉降使其产生旋转位移,围岩土压力变化使衬砌结构内力产生显著变化;随着地裂缝错动位移的发展,上盘内拱顶和下盘拱顶、拱底出现围岩作用的加强,而上盘拱底出现围岩作用的松弛。与隧道正交穿越地裂缝的情况比较,斜交穿越地裂缝时围岩土压力和衬砌结构内力变化更大,易出现拉裂破坏。 相似文献
16.
高水位隧道堵水限排围岩与支护相互作用分析 总被引：2，自引：1，他引：1
为了保护环境并尽可能降低衬砌结构所受的水压力,提出高水位山岭隧道应采取“以堵为主,限量排放”,即“堵水限排”的防排水设计原则。但对于堵水限排情况下衬砌结构的设计,目前尚没有规范可依,这是目前隧道设计施工亟待解决的问题。在隧道力学和渗流力学的基础上进行理论分析,研究渗流应力耦合作用下围岩的力学特性,利用特征曲线法分析了不同排放量下围岩与支护的相互作用,并与数值方法计算结果进行对比。计算结果表明：不同排水量下围岩特性曲线不同,支护阻力也不同,不同排水条件下围岩有效切向应力和有效径向应力的变化很明显,排水对围岩应力以及支护体系受力的影响是不容忽视的。另外,传统隧道设计方法在全排水时完全不考虑水的作用是不安全的。所得结论可为堵水限排衬砌结构设计提供理论依据。 相似文献
17.
Geological and geotechnical investigations of Loharinag-Pala Hydroelectric Project,Garhwal Himalaya,Uttarakhand 总被引：1，自引：0，他引：1
Ajay K. Naithani A. K. Bhatt K. S. Krishna Murthy 《Journal of the Geological Society of India》2009,73(6):821-836
The project area, forming a part of Bhagirathi valley, exposed rocks classed as central Himalayan crystallines and are medium
to high grade metamorphics. The rock types exposed are feldspathic gneisses, quartz-biotite schists, garnet-biotite schist,
biotite gneisses, migmatites and amphibolites. To design the rock support for the underground structures of desilting chambers,
HRT, surge shaft, pressure shafts, power house, TRT and for the foundations of barrage and intake of desilting chambers, rock
mass classifications was attempted following the methods of Bieniawski Rock Mass Rating (RMR) Classification and Tunnelling
Quality Index (Q) of Barton et al. RMR technique involves collection of data on rock strength, RQD (%), spacing of discontinuities,
condition of discontinuities and groundwater condition, while the ‘Q’ involves collection of data on RQD (%), joint set numbers
(Jn), joint roughness number (Jr), joint alternation number (Ja), joint water reduction factor (Jw) and stress reduction factors
(SRF). The permeability test in the overburden was done by the constant head method, while in the bed rock portion conducted
by packer test. The result indicates that the rock masses of the area fall under the good, fair and poor rock quality. Augen
gneiss of power house area is coming under the category of moderately strong rock as proved by deformability characteristics
and strength parameter. On the basis of above study recommendations have been made for the proper and safe construction of
the project components. 相似文献
18.
Karl Gunnar Holter 《Rock Mechanics and Rock Engineering》2014,47(3):1003-1020
A composite tunnel lining system based on a sprayed waterproofing membrane combined with sprayed concrete is currently being considered for future Norwegian rail and road tunnels. Possible loading of the tunnel linings caused by water pressure is being investigated. This tunnel lining system consists of a waterproof membrane which, during application on the sprayed concrete lining, bonds mechanically to the sprayed concrete on either side. Hence, a continuous, sealing, and non-draining structure from the rock mass to the interior tunnel surface is formed in the walls and crown. Experiences from some successful recent projects with this lining system in Europe are reviewed. However, these experiences are not directly comparable to the Scandinavian hard rock tunnel lining approach, which utilizes a relatively thin sprayed and irregular concrete layer for permanent lining. When considering the sprayed membrane and sprayed concrete composite lining concept, introducing a partially sealing and undrained element in the lining, the experiences with the traditionally used lining systems in Norway need to be reconsidered and fully understood. A review of several hard rock tunnels with adverse conditions, in which the tunnel lining has been subject to load monitoring, shows that only very small loads in the tunnel linings occur. Recent investigations with in situ water pressure testing, including two sites with the composite sprayed membrane in a partially drained waterproof tunnel lining, are discussed. In a case with a cavern located in a hydraulically saturated rock mass subjected to approximately 8 bar hydrostatic pressure, a negative pressure gradient towards the tunnel lining has been measured. The investigation results from the Norwegian test sites indicate that no significant loading of the tunnel lining takes place in a hydraulically saturated rock when applying this composite waterproof tunnel lining in parts of the tunnel perimeter. 相似文献
19.
将加、卸载响应比理论引入地下岩体洞室群地震响应分析中。以输入的地震加速度作为加、卸载,以洞室围岩的加速度作为响应,合理地确定了加、卸载响应区段。通过有限差分程序FLAC3D建立了白鹤滩水电站13号机组剖面数值分析模型,选用汶川地震波进行动力时程计算,探讨地下岩体洞室群的地震动力稳定性,研究结果表明：在100年超越概率2%的地震作用下,白鹤滩水电站地下洞室群围岩响应比峰值范围在4.05～11.52之间;结合应力及位移分析,主厂房拱顶及层间错动带C4在尾调室上游边墙出露部位的围岩均进入了非线性变形状态,但响应比在整个时程中并没有趋于无穷大,围岩没有发生失稳破坏;错动带两侧的围岩产生了一定的相对位移,会对尾调室的边墙稳定性产生不利影响。该研究方法可应用于一般地下岩体结构的地震稳定性分析中。 相似文献
20.
J. Hegemann 《Engineering Geology》1981,18(1-4):385-393
For Ruhrkohle AG, the largest mining company of the Federal Republic of Germany, nine shafts are presently being sunk. In late 1978, Gewerkschaft Walter, Essen, obtained the contract for the construction of the Voerde shaft from Bergbau AG Niederrhein, a subsidiary of Ruhrkohle AG.
The requirements to be met regarding the quality of the lining in terms of loads to be absorbed from rock pressure, hydraulic pressure, tension, etc. are very high. Up to a depth of 600 m, this shaft will be sunk through soft and water-bearing strata such as formations of Tertiary, Cretaceous, Bunter Sandstone and Permian. The freezing method therefore has to be employed.
The high requirements with regard to the quality of the lining can only be fulfilled if the lining is constructed in the form of an absolutely watertight tube, not connected to the surrounding ground and resting on a ring foundation below the frozen part of the shaft.
During sinking of the shaft, the icewall will normally absorb the load of both rock pressure and hydraulic pressure. Because of the depth of the frozen part of this shaft and for economical reasons, a yielding outer lining has to be constructed. This will serve on one hand as an auxilliary lining during sinking as a support for the icewall and, as part of the final lining on the other hand, will absorb the rock pressure. This auxilliary lining can only be of the yielding type, its flexibility must correspond to the behavior of the surrounding frozen rock. The determination of the thickness of the icewall and the outer lining was based upon results of tests carried out on frozen and non-frozen drilling cores by Prof. Jessberger's Institute at the Ruhr-University of Bochum.
Taking an outside shaft diameter of approximately 9 m, the diameter of the freezingpipe circle is 18.5 m, the number of freezing pipes is 38.
Considering an icewall-thickness of 8 m (on average) and using the data for friction and cohesion for the different rock formations resulting from the above mentioned tests, the lining dimensions for the different rock formations were calculated. The determined dimensions were widely varying. It also had to be considered, that the outer lining would have to bear the load of the rock pressure once the frozen core of the shaft had been finished. 相似文献