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将多孔介质中井-含水层-隔水层的潮汐水位振幅和位相的计算公式推广到裂隙饱水岩体潮汐分析中,分析了裂隙含水层中井与裂隙,裂隙与微裂隙的潮汐孔压响应原理和水流交换过程,提取了影响裂隙含水层潮汐水位振幅和位相的主要因素,应用井-裂隙排水产生的井水位引潮高的振幅比A和位相差a2主要随径向等效导水系数T同向变化,裂隙和微裂隙(孔隙)排水产生的孔压-引潮高的振幅比D和位相差a1主要随不排水条件下微裂隙与裂隙间振幅比E' /E反向变化的规律,提出了潮汐井水位振幅和位相的8种不同变化类型,分析了不同类型所反映的含水层形变,并用于分析东川、弥勒和西昌川03等3口井井水位振幅和位相变化的成因. 相似文献
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将多孔介质中井-含水层-隔水层的潮汐水位振幅和位相的计算公式推广到裂隙饱水岩体潮汐分析中, 分析了裂隙含水层中井与裂隙, 裂隙与微裂隙的潮汐孔压响应原理和水流交换过程, 提取了影响裂隙含水层潮汐水位振幅和位相的主要因素, 应用井-裂隙排水产生的井水位-引潮高的振幅比A和位相差α2主要随径向等效导水系数T同向变化, 裂隙和微裂隙(孔隙)排水产生的孔压-引潮高的振幅比D和位相差α1主要随不排水条件下微裂隙与裂隙间振幅比E'/E反向变化的规律, 提出了潮汐井水位振幅和位相的8种不同变化类型, 分析了不同类型所反映的含水层形变, 并用于分析东川、 弥勒和西昌川03等3口井井水位振幅和位相变化的成因. 相似文献
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为定量刻画地壳应力-应变改变、含水层孔压扰动及井孔水位变化之间的耦合过程,促进对近场地震水位同震响应机制的理解,利用多场耦合数值模拟方法,获得鲁甸地区（200×200）km2范围内,2014年鲁甸MS6.5地震造成的同震静态应变场分布、孔压演化规律及会泽井水位响应曲线,并以渗透系数、杨氏模量及孔隙度为变量,设计6组不同模拟情景对影响研究区孔压演化的参数进行分析。结果表明：（1）鲁甸地震造成的同震静态应变场沿断层两侧呈四象限分布,应变场极值点分布在断层北段两侧,远离断层体应变数值逐渐减小;（2）地震造成研究区含水层孔压扰动在50 d内恢复至震前稳定值,孔压的扩散时间受渗透系数及杨氏模量的影响;（3）模拟所得会泽井水位受地震影响瞬时上升0.45 m,并在震后50 d内恢复至震前水位,水位变化趋势为阶升之后缓慢恢复,模拟水位与实测水位变化趋势相近。 相似文献
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本文详细介绍了地球内部应变和应力固体潮的计算理论,基于PREM地球模型计算了地球内部的Love数,并计算了地球内部的应力和应变的6个独立分量在不同深度和纬度处的时间变化序列.结果表明:应力潮汐的振幅达到103Pa,应变潮汐振幅达到10-8;不管应力或是应变潮汐,其振幅随深度的不同都有较大的变化;6个应力和应变分量对纬度依赖较大,但没有表现出南北纬度上的严格的对称性,与纬度的对应关系由引潮位展开的大地系数确定.本文结果可有效应用于地球内部应变或应力潮汐观测的固体潮改正;另外,将本文结果应用于研究潮汐触发地震问题,给出了中国中部地区的一个算例,结果表明地震断层正应力潮汐和应力张量第一不变量潮汐与发震时刻具有明显的相关性,而这种相关性并未在其他如剪切应力以及库伦破坏应力潮汐中表现出来. 相似文献
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钻孔应变观测系统（岩石、 膨胀水泥和应变仪钢筒）存在显著的井孔耦合效应,只有确定这一耦合系数,才能得到地壳岩石的真实应变值,从而实现不同测点数据的可比性．本文根据双衬套理论及弹性力学理论,建立了三维空间应力作用下体应变与面应变观测力学模型,并进一步推导各自井孔耦合系数计算式,发现两组系数与井孔的受力状况密切相关,分别与不同力源引起的应变信号相对应．亦即应力比（钻孔轴向应力与平面应力之比）不同,耦合系数也不一样,体应变随应力比的增大而下降,面应变则上升. 本文结果还表明平面应力作用下的耦合系数与外加应力无关,只与观测系统本身有关,故数值保持恒定. 此外,文中对其影响因素也进行了分析,结果表明,体应变和面应变的井孔耦合系数均随岩石弹性模量和泊松系数的增大而增大,且前者的幅度较大,井孔耦合材料水泥对二者影响均很小． 相似文献
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根据地震前兆的"应力-应变原理",以及"岩石变形破坏的实质是其孔隙度发生变化"的结论,进一步应用地下水动力学中的达西定律推导得出,饱和含水层井孔在恒定流量下的动水位与该井孔静水位之差或二种不同恒定流量下的动水位之差ΔH,可以相对量度饱和含水层岩体孔隙度的变化,进而得出相对量度岩体受力变形的动态变化过程,这可作为一项新的地震前兆指标。据此设计了一种以"井孔ΔH指标"为观测对象的新型地震前兆观测系统。理论分析得出,ΔH指标仅对地下深部岩体应力-应变的变化信息敏感,对非应力-应变因素和地表干扰不敏感。已有实验初步验证了其具有抗干扰、高灵敏度和高信噪比等特性。距离实验点400km的2002年3月31日台湾花莲海外7.5级地震为ΔH指标的可行性实验提供了一个例证。 相似文献
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根据双衬套钻孔应变观测力学模型,推导出平面应力作用下各分量应变观测中两个耦合系数(A、B)的计算公式,为进一步确定地壳应变场最大、最小主应变的数值及方向提供了必需的前提条件,对当前国内外开展的利用钻孔应变进行地震、火山和板块边界的观测研究具有一定积极意义.研究结果表明,A、B与用双环模型和复变函数法解算出的c(面应变响应因子)、d(剪应变响应因子)之间分别存在2倍的关系(c=2A,d=2B),并且二者绘制的曲线完全一致,c、d的物理含义分别是地壳岩石面应变与剪应变观测的井孔耦合系数. 相似文献
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本文讨论了在构造应力水平达到岩石破裂临界值时引潮力、潮汐附加应力的动态变化与地震序列之间的关系，选用了中国大陆1970年以来7级以上地震序列资料，分析了引潮力水平分量动态变化与强震发震时间之间的关系，结果显示在一定时空范围内前震、主震及余震序列发震时刻的引潮力存在优势方向，多数地震发震时刻与选取时段引潮力水平分量的方位角相位比平均值仅为35%；对于构造复杂地区，结果显示引潮力水平分量的方位角不仅存在一个优势方向，还明显存在其他优势方向，可能与发震构造有关.根据1966～1976年中国九大地震震源机制解计算潮汐正应力和滑动方向的剪应力及其变化率，结果显示多数地震发震时刻潮汐剪应力接近最大值. 相似文献
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In this paper,the mechanical response of saturated geological rock under tidal force is explored by poroelastic theory.First,we use the free energy formula of saturated rock under a tidal force to study the relationships of pore pressure with stress,and stress with strain.Then we analyze the relationship between rock strain and tidal potential by the equilibrium differential equations of saturated rock under tidal force.Finally,we derive the physical relationship between the two parameters (pore pressure and tidal mean stress) of saturated rock and tidal potential.The relationship shows that:pore pressure is directly proportional with tidal potential,but tidal mean stress of saturated rock is inversely proportional with tidal potential.The ratio coefficient is related not only to the Lame coefficients of rock skeletons,but also to the Biot modulus.By using this model to analyze observational well water level of C-18 well which locates in Huili,Sichuan Province,the well level response coefficient (D) was estimated.This way,we derive the Skempton coefficient (B),the coefficient A and C which refer to the response coefficients of pore pressure and tidal stress to tidal potential respectively.Then we compare the differences among each coefficient in coupling and uncoupling conditions.It shows that for saturated rocks,the response of stress and pore pressure to earth tides is a product of coupling,and it is necessary to take into account the coupling effect when we study the mechanical response.The model will provide the basis not only for the study of mechanics and hydrodynamics of well-confined aquifer systems,and the mechanics of faulting under tidal force,but also for quantitative research of the triggering mechanism of tidal forces. 相似文献
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本文基于井水位微动态对固体潮和大气压响应的物理机制, 运用水-岩耦合理论, 建立了井水位对固体潮-气压综合作用的响应模型。 以邛崃川22井和南溪川12井为例, 通过井水位与固体潮和气压原始曲线的对比及拟合分析, 对井水位对固体潮-气压综合作用的响应模型进行了验证。 结果表明, 两口井对固体潮-气压综合响应非常好, 井水位的变化均由固体潮和气压变化引起。 两口观测井中, 以南溪川12井的水位综合响应能力较好, 邛崃川22井水位受到较多的杂讯干扰, 水位曲线日变化较复杂。 对邛崃川22井进一步分析表明, 利用井水位时段平均值可有效消除观测误差, 用小时值计算时可以忽略井水位对气压响应的滞后效应。 相似文献
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基于流体及岩石力学理论，利用气压和潮汐效应，研究了苏皖地区苏02井、苏03井、苏06井、苏18井和定远04井含水层介质在不排水状态下孔隙度和渗透系数的变化情况.结合井-含水层系统在受力和水均衡两种状态下的微动态变化模型，分析了各井水位自2014年下半年以来相继出现同步上升现象的水动力学成因机制.结果表明:① 5口井的气压系数与M2波潮汐因子之间存在明显的线性关系，即气压系数越大，潮汐因子也越大；②各井的孔隙度和渗透系数出现一组同步增大现象，主要与补给量大于泄流量、补给增强有关. 相似文献
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The coupled mechanics of fluid-filled granular media controls the physics of many Earth systems, for example saturated soils, fault gouge, and landslide shear zones. It is well established that when the pore fluid pressure rises, the shear resistance of fluid-filled granular systems decreases, and, as a result, catastrophic events such as soil liquefaction, earthquakes, and accelerating landslides may be triggered. Alternatively, when the pore pressure drops, the shear resistance of these geosystems increases. Despite the great importance of the coupled mechanics of grain–fluid systems, the basic physics that controls this coupling is far from understood. Fundamental questions that must be addressed include: what are the processes that control pore fluid pressurization and depressurization in response to deformation of the granular skeleton? and how do variations of pore pressure affect the mechanical strength of the grains skeleton? To answer these questions, a formulation for the pore fluid pressure and flow has been developed from mass and momentum conservation, and is coupled with a granular dynamics algorithm that solves the grain dynamics, to form a fully coupled model. The pore fluid formulation reveals that the evolution of pore pressure obeys viscoelastic rheology in response to pore space variations. Under undrained conditions elastic-like behavior dominates and leads to a linear relationship between pore pressure and overall volumetric strain. Viscous-like behavior dominates under well-drained conditions and leads to a linear relationship between pore pressure and volumetric strain rate. Numerical simulations reveal the possibility of liquefaction under drained and initially over-compacted conditions, which were often believed to be resistant to liquefaction. Under such conditions liquefaction occurs during short compactive phases that punctuate the overall dilative trend. In addition, the previously recognized generation of elevated pore pressure under undrained compactive conditions is observed. Simulations also show that during liquefaction events stress chains are detached, the external load becomes completely supported by the pressurized pore fluid, and shear resistance vanishes. 相似文献
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— Rock-stress measurements performed in boreholes drilled from a tunnel at a depth of 800 m indicate that the minimum stress has been reduced from pre-excavation levels by drawdown in pore pressure. The disturbance to the ambient stresses extends well beyond two tunnel diameters. A model is developed to explain the inferred strong coupling between the pore pressure and minimum stress in the rock mass around the tunnel. The model includes the effects of poro-elasticity of the intact rock and the stiffness of the fractures. For the field situation under study where the fractures are unusually complaint, both poro-elasticity and fracture compliance could be important contributors to the coupling. Changes in pore pressure are shown to produce reductions in minimum stress that are at least 50% of the drop in pore pressure and probably higher. In more general situations, the poro-elastic component is likely to be the more significant of the two mechanisms and alone accounts for a coupling factor of 50%. In this context, the importance of fractures in crystalline conditions probably lies more in their promotion of penetrative drainage than their contribution to coupling coefficient. The results highlight the importance of establishing the extent and distribution of pore pressure drawdown about galleries from which stress measurements are to be conducted. 相似文献
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孔隙压力参数是用来表述饱和岩土受力变形时所受力与超孔隙压力关系的参数,是地震地下水前兆机理研究中的重要问题。本文从室内试验、现场试验与野外观测的某些结果,分析了不同岩土、不同受力条件下孔隙压力参数的若干特征 相似文献
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Hydrogeological parameter is an important index to characterize the hydrogeological properties of the aquifer, and has a clear physical basis and mechanism. Although the predecessors have made significant achievements in these areas, research is lacking on the changing law and relationship of the hydrogeological parameters of well-aquifer system. The digital water level and barometric pressure data of Dadianzi Well are used as the basis in this study. Based on the theories of elastic mechanics, rock mechanics and fluid mechanics, and using barometric pressure coefficient and tidal factor, the hydrogeological parameters in Dadianzi well-aquifer system in undrained conditions are studied. The corresponding water storage rate can also be obtained quantitatively. In addition, with the thickness of the aquifer, the pressure transmitting coefficient, the radius of the well and the frequency of the tidal wave, the permeability coefficient and transmissibility coefficient of well-aquifer system can be obtained, and the relationships between them are derived. The results show that: 1)There is an obvious power function relationship between porosity and solid skeleton volume compression coefficient, volume compression coefficient of water in aquifer, water storage rate, permeability coefficient and transmissibility coefficient. The volume compression coefficient of solid skeleton, water storage rate, permeability coefficient and transmissibility coefficient have a positive correlation with the porosity, the volume compression coefficient of water in aquifer decreases with increasing porosity. The volume compression coefficient of solid skeleton and water in aquifer can be well fitted to one of two quadratic polynomials. And the volume compression coefficient of water in aquifer is larger than the solid skeleton volume compression coefficient, water is more easily compressed. In addition, with the increase of water storage rate, the permeability coefficient and transmissibility coefficient also increase linearly; 2)Different from the traditional pumping test and indoor experiment, this paper uses the digital water level and other data, combined with the pressure coefficient and Venedikov tidal harmonic analysis results to access to the porosity, the volume compression coefficient of solid skeleton and water in aquifer medium, water storage rate, the permeability coefficient and the transmissibility coefficient. This method is simple and accurate. 相似文献
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基于ABAQUS软件平台,应用自行开发的流固耦合动力模型孔压单元模拟场地土体,并通过黏弹性人工边界方法实现地震动的输入,对饱和土体场地中的双孔隧道结构在地震荷载作用下的动力反应进行研究。计算结果表明:在地震反应结束时刻,场地土体位移幅值在两隧道之间以及两隧道的附近区域较大,而远离隧道的区域则较小;场地底部区域土体的孔压幅值较大,而场地顶部区域土体则较小;隧道左右两侧拱腰部位的衬砌的应力较大,而拱顶部位则较小。计算结果同时表明了流固耦合动力模型孔压单元在饱和土体-隧道体系地震反应研究中的适用性。 相似文献