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隧道涌水量预测对隧道的设计和施工至关重要,相关勘察规范要求在一定阶段预测隧道涌水量。目前有多种方法用于预测隧道涌水量,但每种方法都有其适用范围。通过对这些方法进行分析,结合对实际隧道工程涌水量的预测,对于裂隙岩体中的隧道,要准确预测隧道涌水量,需要解决两个问题:地下水位和渗透系数。以钻孔水位为基础,利用物探技术,建立等效的虚拟基岩裂隙水连续水位线。渗透系数一般由钻孔水文地质试验测得,在涌水预测时,应根据优势结构面产状进行修正。 相似文献
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由于岩溶区隧道穿越空间的复杂性、多变性和特殊性,加之地区差异性和水文循环系统的不确定性,各类预测方法均存在其自身的缺点,致使涌水量预测与实际存在一定差异。从水文机理和岩溶水的运动特征出发,结合岩溶区快速补给与慢速补给的差异与特征,采用水均衡法、地下水径流模数法和隧道涌水专家评判系统3种方法,对金奎地特长隧道岩溶涌水进行预测分析。结果显示,水均衡法计算结果值最大,径流模数法计算结果值最小,专家评判系统计算结果值在二者之间。经验证,专家评判系统更为精确,该方法强调次降雨对隧道岩溶涌水的作用,提高了隧道岩溶涌水量预测的精度。 相似文献
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沪蓉高速公路乌池坝隧道区岩溶发育特征及其涌水分析 总被引:3,自引:3,他引:0
乌池坝隧道区有6种岩溶地貌类型,涉及2个岩溶水系统(3条地下河)。其中白岩坝地下河发育受碳酸盐岩层组类型控制,管道结构单一,具有侧向补给、纵向排泄的水文地质特征;龙潭和毛田地下河发育受构造控制,具有多分支、多级排泄的特征。本文将乌池坝隧道分成3部分5个岩溶区段,评价了各区段岩溶发育对隧道涌水的影响,认为从ZK256+300至ZK257+000段,岩溶涌水可能性极大。采用大气降水入渗系数法和地下水疏干法,对各岩溶区段隧道涌水进行计算预测,其中ZK256+300至ZK257+500段涌水量达31.3×10^4m^3/d。[ 相似文献
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重庆南山隧道工程涌水隐患研究 总被引:3,自引:3,他引:0
运用地下水动力学法计算隧道涌水影响半径,采用地下水动力学法、古德曼经验公式,经验解析法公式计算涌水量,并比较中梁山铁路隧道修建对漏水的影响,得到以下结论:(1)从涌水半径来看,南山隧道涌水半径(642m)比轻轨隧道涌水半径(727m)小。轻轨隧道高程较南山隧道高程低,因此轻轨隧道拦截了一部分集雨面积,使得南山隧道涌水量降低。(2)科斯加科夫渗透入量法结果与调查结果更为接近。(3)涂山湖大湖漏水的影响远远小于小湖。这可从中梁山隧道引起的漏水得到启示。涂山湖在南山隧道的影响半径之内,其中大湖因为泥沙淤积时间长,因此受影响小,涂山湖的小湖因为成湖时间不长,因此受影响大。同时要注意南山隧道漏水,浮托力消失,在隧道漏水影响范围内注意岩溶塌陷的隐患。在积极面对南山隧道漏水可能存在的隐患之外,还应该调动群众的力量,将损失影响减少到最小。 相似文献
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蓟县系雾迷山组是天津主力开发的热储层位,对这套地层的研究主要集中在热储层温度场、动力场、水化学场和地表水回灌等方面,在热储岩溶裂隙方面的研究较少。通过对天津市138眼雾迷山组地热井的完井和测井资料进行对比分析,统计了不同构造单元雾迷山组一、二类裂缝发育,热储顶板埋深,地热井单位涌水量和上覆不同地层的情况,总结了其岩溶裂隙发育规律。结果表明:雾迷山组岩溶裂隙较发育,漏失部位距热储顶板埋深距离集中在100 m以浅;热储顶部岩溶发育,裂隙发育受上覆不同地层的影响不大,裂隙发育与该层顶板埋深的相关性不明显,但整体上有裂隙发育随顶板埋深加大而略有减小的趋势;地热井的单位涌水量随裂隙发育程度的增大而变大;热储裂隙比集中在0.1~0.4,受构造影响,在张性断裂构造带、断裂交汇和背斜轴部热储构造裂隙较发育。研究结果可为天津市雾迷山组地热的有效开发利用与地热钻探提供参考。 相似文献
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根据工程应用的目的不同将隧道的涌水量划分为施工涌水量和长期涌水量,针对涌水量预测方法常常存在使用不当的问题,在全面分析隧道涌水量预测方法的适用条件的基础上,按不同的水文地质条件提出了正确选择隧道涌水量预测方法及其计算参数的建议。 相似文献
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本文针对软岩工程中围岩流变大变形问题,以有限变形力学理论为依据,采用更新拖带坐标法编制非线性大变形有限元计算程序,对软岩巷道流变大变形问题进行了数值模拟计算。在计算中,选用了适合描述软岩流变大变形的物性方程,并考虑了锚杆和拱两种支护方式。结合表明,本文采用的理论和计算方法合理,计算程序具有精度高、收敛速度快等优点,展示了良好的应用前景。 相似文献
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Summary The visco-plastic behaviour of rocks plays a relevant role in the tunnelling works, especially for deep tunnels subjected
to large initial stresses for which squeezing conditions may develop. A rheological model is discussed that accounts for visco-elastic
(primary) and visco-plastic (secondary) contributions to rock creep. The effects of tertiary creep are included in the model
by way of a gradual mechanical damage governed by the cumulated visco-plastic strains. The parameters of the intact rock are
first identified based on laboratory test results presented in the literature. Then, after scaling them to those of the rock
mass, the potential applicability of the model is tested through axisymmetric and plane strain finite element analyses of
the full face excavation of a deep circular tunnel. The results are discussed with particular reference to the short term
redistribution of stresses around the opening and to its convergence. The analyses show the relevant influence of tertiary
creep on the tunnel closure. In addition, those based on an axisymmetric scheme turn out to be crucial for the correct long
term prediction of the interaction between the rock mass and the supporting structure of the opening. 相似文献
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Alteration of the oceanic crust: Implications for geochemical cycles of lithium and boron 总被引:1,自引:0,他引:1
Fresh tholeiitic basalt glass has been reacted with seawater at 150°C, (water/rock mass ratio of 10), and fresh diabase has been reacted with a Na-K-Ca-Cl fluid at 375°C (water/rock mass ratios of 1, 2, and 5) to understand better the role of temperature, basalt composition, and water/rock mass ratio on the direction and magnitude of B and Li exchange during basalt alteration. At 150°C, slight but nevertheless significant amounts of B and Li were removed from seawater and incorporated into a dominantly smectite alteration phase. At 375°C, however, B and Li were leached from basalt. B behaved as a “soluble” element and attained concentrations in solution limited only by the B concentration in basalt and the water/rock mass ratio. Li, however, was less mobile. For example, at water/rock mass ratios of 1, 2, and 5, the percent of Li leached from basalt was 58, 70, and 92% respectively. This suggests some mineralogic control on Li mobility during hydrothermal alteration of basalt, especially at low-water/rock mass ratios. In general, these results, as well as those for B, are consistent with the temperature-dependent chemistry of altered seafloor basalt and the chemistry of ridge crest hydrothermal fluids.Based on the distribution and chemistry of products of seafloor weathering, low (≤ 150°C) and high-temperature hydrothermal alteration of basalt, and the chemistry of ridge crest hydrothermal fluids, it was estimated that alteration of the oceanic crust is a Li source for seawater. This is not true for B, however, since the hot spring flux estimated for B is balanced by low-temperature basalt alteration. These data, coupled with B and Li flux estimates for other processes (e.g., continental weathering, clay mineral adsorption, authigenic silicate formation and formation of siliceous skeletal material) yield new insight into the B and Li geochemical cycles. Calculations performed here indicate relatively good agreement between the magnitude of B and Li sources and sinks. The geochemical cycle of B, however, may be affected by serpentinization of mantle derived peridotite in oceanic fracture zones. Serpentinites are conspicuously enriched in B and if the B source for these rocks is seawater, then an additional B sink exists which must be integrated into the B geochemical cycle. However, until more data are available in terms of areal extent of serpentinization, serpentite chemistry and isotopic composition, the importance of B in these rocks with respect to the B geochemical cycle remains speculative at best. 相似文献
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浅埋隧道围岩应力场的计算复变函数求解法 总被引:2,自引:1,他引:1
对于受地表边界和地面荷载影响的浅埋隧道的围岩应力场,由于在数学处理上存在一定的困难,很难用解析解来进行分析,而通常采用边界元或有限元的数值方法来解答。为了求解浅埋隧道的应力场,采用边界配点来确定边界条件,同时用保角映射将一个含圆孔的半无限空间区域映射为圆环域,然后把这个区域内的解析函数展开成Laurent级数的形式,利用Muskhelishvili的复变函数理论和最小二乘法来确定解析函数的各项系数,从而求得浅埋隧道围岩压力的半数值、半解析解,最后通过算例给出了围岩应力的分布情况。计算结果表明,该方法计算精度高、计算量小,具有应用价值。 相似文献
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湖北清江水布垭导流洞采用矿山法施工,为确保施工安全,以三维有限元对该隧洞处于断层破碎带的进口渐变段的施工过程进行了计算模拟,并根据计算结果确定了合理的施工方案.根据地下结构设计理论中的地层结构法,选用连续体计算模型,对围岩材料和混凝土材料的本构关系分别作理想弹塑性应力-应变关系和线弹性本构关系的简化,并采用摩尔-库仑屈服准则,分析了初期支护结构的受力特点、围岩塑性区的深度和范围以及洞周围岩位移的发展规律.结果显示,围岩塑性区深度较大,而且初期支护结构承受的最大拉、压应力均略大于混凝土的强度极限,指出该区段初期支护结构在采用钢筋格栅喷混凝土的基础上,应加强长、短系统锚杆进行围岩加固. 相似文献
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不同埋置深度的山岭隧道地震响应分析 总被引:2,自引:0,他引:2
根据大量震害资料的调查分析发现,地下结构埋置深度对其地震破坏程度影响很大。通过有限元方法计算8种不同埋置深度条件下的山岭隧道地震响应,并对计算模型的地震输入方法进行了验证,证明地震波输入处理方式的合理性。讨论埋深对结构动力响应的影响,提取衬砌关键节点的竖直向和水平向加速度、位移峰值,分析随着埋深的增大,加速度和位移峰值的变化情况,并以拱顶为例,计算每个埋深变化段的加速度和位移峰值变化率,得到了一定的规律性,如埋置深度从5 m增大到50 m,衬砌结构动力响应峰值大小下降较快。此外,还分析了埋深增大对衬砌结构内力峰值的影响。最后,提出在高烈度地震区修建隧道时其埋置深度尽可能不小于50 m,这为相关工程的修建提供了参考依据。 相似文献