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排序方式: 共有233条查询结果,搜索用时 203 毫秒
81.
引水隧道施工中屡次发生坍塌,用探地雷达对衬砌质量及地质情况进行探测。经数据反演,清晰勾画出衬砌背后空洞、松散堆积体分布范围,地下水的赋存特征,为治理事故提供切实可靠依据。 相似文献
82.
83.
江西井冈山鹅岭隧道是新建衡阳-茶陵-吉安铁路的关键性控制工程,洞身全长10 455 m,最大埋深750 m。该隧
道的地质构造复杂,断裂发育,岩石破碎,水量丰富。其涌水量是该隧道设计和施工的重要参数。在区域地质和构造调
查的基础上,本研究选择不同渗水岩性段进行了多口钻井(DK)及其水文地质试验,获得了一批宝贵的第一手隧道工程
地质和水文地质资料和数据。通过对这些资料和数据的分析和研究,确定了不同地质体的出水量和渗透系数。继而,按
钻井位置将该隧道划分为9 个不同涌水区段,运用不同方法对各个区段的涌水量进行了精细计算,预测5 个区段涌水量大,
分别为DK7+280-DK7+550(最大赋水段)、DK6+625-DK7+280(中等赋水段)、DK8+875-DK10+085(中等赋水段)、
DK11+570-DK11+770(中等赋水段)和DK13+570-DK13+930(中等赋水段),施工过程中很可能产生突发涌水现象,建
议施工设计中采取有效防护措施,高度重视这些区段的工程质量。实践证明,本文的研究结果对嗣后的该隧道设计和施工
发挥了积极的指导作用,提高了施工质量。 相似文献
84.
The geomorphology of troughs crossing the Antarctic shelf is described and interpreted in terms of ice-stream hydrology. The scale of tunnel channels on the inner shelf and the absence of sediment at their mouths are taken to infer catastrophic drainage. Drumlins on the inner and outer shelves with pronounced crescentic and hairpin scours are also interpreted as products of catastrophic flow. Gullies and channels on the continental slope and turbidites on the rise and abyssal plain point to abundant meltwater discharge across the shelf. Attempts to explain this morphology and sedimentology in terms of release or discharge of meltwater by pressure melting, strain heating, Darcian flow, or advection in deforming till are shown to be unrealistic. We suggest that meltwater flow across the middle and outer shelves might have been in broad, turbulent floods, which raises the possibility that megascale glacial lineations (MSGL) on the shelf might originate by erosion in turbulent flow. This possibility is explored by use of analogs for MSGL from flood and eolian landscapes and marine environments. An extended discussion reflects on objections that stand in the way of the flood hypothesis. 相似文献
85.
深埋长隧洞地质超前预报技术 总被引:3,自引:0,他引:3
周春宏 《地质灾害与环境保护》2005,16(4):419-424
国内外已建成的各种不同用途的隧洞在掘进施工过程中常因发生不同程度的塌方、涌水、碎屑流、离地温、高地应力及岩爆、高瓦斯等地质灾害,考虑到我国近期有一系列深埋长隧洞工程,如南水北调西线工程、大伙房调水工程、锦屏二级水电站超深埋引水隧洞等急待建设工程,为避免施工过程中发生不可预见的地质灾害,故在工程施工过程中应加强地质超前预报工作,以减少投资风险.而提高预报的成功率则显得十分重要。 相似文献
86.
This paper presents an engineering approach for analysing the longitudinal behaviour of tunnels subjected to earthquakes. The tunnel is modelled as a Timoshenko beam connected to the far soil by means of continuous elastic support (Winkler model). Seismic free-field inputs, such as those caused by surface waves travelling parallel to the tunnel axis, were imposed at the base of the springs of the Winkler model, generating bending moments and shear forces on the cross-sections of the tunnel. Closed-form expressions of the tunnel displacements, shear forces, and bending moments were determined at any tunnel section in terms of the seismic excitation, tunnel geometry and material properties, and subgrade reaction modulus of the soil. A dimensional analysis was carried out to ascertain directly the maximum tunnel displacement, bending moment, and shear force. 相似文献
87.
88.
In this study, a series of centrifuge tests, modeling reverse fault rupture with 60° dip angle, were conducted in a dry sandy soil with a tunnel embedded in the soil layer. The test results showed that the tunnel and soil responses depended on the tunnel position, soil relative density and tunnel rigidity. Tunnels appeared be able to deviate the fault rupture path, while this deviation may be associated with significant rotation and displacement of the tunnel. However, a deeper tunnel was able to diffuse the shear deformation to a wider zone with an unsmooth surface displacement which may cause severe damage to the surface structures. Finally, the tunnel rotation, the location of the fault outcropping, the vertical displacement of the ground surface, the effect of tunnel rigidity on fault rupture path and surface displacement and the effect of soil relative density on fault–tunnel interaction were reported and discussed in this study. 相似文献
89.
电阻率测深数据可利用抗道的四个面和四个角得到。但由于受到坑道本身和体积效应影响,坑道内电阻率测深资料解释的困难很大。本文用有限单元法对坑道内的直流电阻率测深进行数值模拟计算。首先给出坑道中正常电位的取值,并利用有限单元异常电位计算法对坑道内电阻率测深进行正演计算。结果表明,在异常体断面尺寸、埋深及所用电极距与坑道截面尺寸相差不大时,坑道面上的测深断面反映的基本是本坑道面外侧地质体的信息,对其他位置的地质体没有明显反映,坑道角断面则反映的是相邻两个坑道面外侧地质体的综合信息。 相似文献
90.
In this paper a detailed engineering geological assessment of rock masses and support design studies at Garmi Chay dam site, has been carried out. This project is located in the northwest of Iran and will be used for flow control and water storage. The diversion tunnel of the dam has a diameter of 5.5 m and a length of 420 m and will be driven in slightly to highly weathered micaschist and trachy andesite rock units. The geological studies include field and laboratory investigations that based on the results; for more exact investigation, tunnel alignment was divided into three geotechnical zones. These zones consist mainly of highly weathered gray micaschists, dark red trachy andesites and slightly weathered gray micaschists, respectively. Then, for every zone, support capacity of rock masses was evaluated by means of empirical and numerical methods. The rock mass classification systems (RMR, Q, GSI, RSR, SRC and RMi), the convergence–confinement method and a 2D finite element computer software, Phase2 were used for empirical and numerical method, respectively. According to the results acquired from these methods some stability problems were expected in the tunnel especially in highly weathered micaschist zone, so that in practice two big collapses occurred. Because of high weathering, low constants of rock masses and their soil-like behavior, the stability analysis by analytical method does not give illogical results in lightly weathered micaschist zone. The support system, suggested by empirical method, was applied and its performance was evaluated by means of numerical modeling. After installation the support suggested by Phase2 program, the thickness of plastic zone and deformations around the tunnel decreased significantly. Consequently the agreement of these methods with each other was resulted and using combination of them was recommended for more reliable support design. 相似文献