共查询到20条相似文献，搜索用时 12 毫秒
1.
张量CSAMT数据处理技术初步研究与示范应用 总被引：1，自引：0，他引：1
面对大深度和三维探测,标量CSAMT(controlled source audio-frequency magnetotellurics)已显力不从心,而张量CSAMT正逐渐成为研究热点。在前人研究基础上,笔者就张量CSAMT数据处理方面提出Mohr圆分析和传统坐标旋转两种处理技术,并首次创新性地使用我国自主研发的综合电法仪开展了张量CSAMT示范应用。结果表明:Mohr圆分析和传统坐标旋转法相结合应用效果良好,可定性挖掘地下地质体的纵向和横向构造特征,主轴方位的视电阻率和阻抗相位与目标体对应良好,并且电阻率反演结果与钻孔等地质资料综合分析对建立试验区的地质地球物理模型是有益的。 相似文献
2.
Susan H. Treagus 《Geological Journal》1987,22(2):119-132
The Mohr circle is a well known representation of two-dimensional strain. It is commonly used to illustrate strain algebra, or derive a strain ellipse from particular strain data. The established sign convention is positive (anticlockwise) shear strain on the upward ordinate, after Brace. However, in practice, confusion may easily arise from inconsistent conventions in standard text books. A Mohr-circle convention is proposed here which represents clockwise shear strain on the upward γ ordinate (i.e. upside-down). It simplifies the Mohr circle by representing both single and double angles in their natural sense. Single angles may be traced from rock to Mohr circle directly which is not the case for the Brace circle. Deformed brachiopods and stretched belemnites are used to illustrate this simplified Mohr circle. The pole to the Mohr circle is a useful addition which allows strain data to be represented in their true orientation. The pole method only works on the γ clockwise-up Mohr circle. The Mohr circle is useful to demonstrate simple-shear geometry and algebra. Successive Mohr circles with poles may be used to map strain across a heterogeneous simple-shear zone. 相似文献
3.
W.D. Means 《Tectonophysics》1982,89(4):T1-T6
Mohr circles for the stretch tensor and the reciprocal stretch tensor are described. They have the useful property that the polar coordinates of points on the circles are the stretches and rotations of material lines. 相似文献
4.
Lain Allison 《Journal of Structural Geology》1984,6(3):331-333
The pole of a Mohr diagram, for the two-dimensional case, is a unique point on the Mohr circle which permits any point on the Mohr circle to be related to the direction in the physical plane associated with that point. A Mohr diagram can be constructed for any second rank tensor. To illustrate the simplicity of this geometrical construction two examples of the use of the pole are presented, one for the strain tensor and the other for the stress tensor. 相似文献
5.
This paper discusses the quality of the procedure employed in identifying soil parameters by inverse analysis. This procedure includes a FEM‐simulation for which two constitutive models—a linear elastic perfectly plastic Mohr–Coulomb model and a strain‐hardening elasto‐plastic model—are successively considered. Two kinds of optimization algorithms have been used: a deterministic simplex method and a stochastic genetic method. The soil data come from the results of two pressuremeter tests, complemented by triaxial and resonant column testing. First, the inverse analysis has been performed separately on each pressuremeter test. The genetic method presents the advantage of providing a collection of satisfactory solutions, among which a geotechnical engineer has to choose the optimal one based on his scientific background and/or additional analyses based on further experimental test results. This advantage is enhanced when all the constitutive parameters sensitive to the considered problem have to be identified without restrictions in the search space. Second, the experimental values of the two pressuremeter tests have been processed simultaneously, so that the inverse analysis becomes a multi‐objective optimization problem. The genetic method allows the user to choose the most suitable parameter set according to the Pareto frontier and to guarantee the coherence between the tests. The sets of optimized parameters obtained from inverse analyses are then used to calculate the response of a spread footing, which is part of a predictive benchmark. The numerical results with respect to both the constitutive models and the inverse analysis procedure are discussed. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
6.
A simple method called anisotropic transformed stress (ATS) method is proposed to develop failure criteria and constitutive models for anisotropic soils. In this method, stress components in different directions are modified differently in order to reflect the effect of anisotropy. It includes two steps of mapping of stress. First, a modified stress tensor is introduced, which is a symmetric multiplication of stress tensor and fabric tensor. In the modified stress space, anisotropic soils can be treated to be isotropic. Second, a TS tensor is derived from the modified stress tensor for the convenience of developing anisotropic constitutive models to account for the effect of intermediate principal stress. By replacing the ordinary stress tensor with the TS tensor directly, the unified hardening model is extended to model the anisotropic deformation of soils. Anisotropic Lade's criterion is adopted for shear yield and shear failure in the model. The form of the original model formulations remains unchanged, and the model parameters are independent of the loading direction. Good agreement between the experimental results and predictions of the anisotropic unified hardening model is observed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
7.
本文介绍了地质插图系统的研究和设计的环境和设计原理,首先,分析了地质插图的复杂性,其次,讨论图形如何分类,分析各种地质要素,建立各种模块来实现地质需求,最后,阐述进一步研究的方向和目标,系统主要解决各种地质报告和书籍的图文编辑中图形的生成、编辑和最终成果提供的Ｗｉｎｄｏｗｓ位图等系列问题。 相似文献
8.
《Russian Geology and Geophysics》2016,57(6):967-983
This study continues the work by Mikhail Gzovsky on geological (tectonophysical) criteria for seismic risk. It is suggested to perform seismic-risk zoning according to parameters of normal and shear stresses on fault planes converted from results of tectonophysical stress reconstructions. The approach requires the knowledge of both dip and strike of the respective fault segments. Slip geometry is estimated from stress tensor, assuming that it is directed along shear stress. The suggested approach is applied to faults in the northern Tien Shan, and the current stress parameters are reconstructed using source mechanisms of catalogued earthquakes recorded by the KNET seismological network of the RAS Science Station in Bishkek. Stress modeling is performed by the method of cataclastic analysis providing constraints on stress ellipsoids, as well as on relations between the spherical and deviatoric components of the stress tensor. Plotted on the Mohr diagram, the fault stress points allow estimating whether the respective fault segments are close to the critical state (brittle failure). The suggested seismic-risk zoning of faults in the northern Tien Shan reveals up to 25 km long hazardous fault segments. 相似文献
9.
卸荷条件下岩石变形特征及本构模型研究 总被引：11，自引：0，他引：11
基于岩石试件的卸荷试验,研究了卸荷条件下岩石的应力—应变全过程曲线和破裂特征,研究表明：卸荷过程中岩石向卸荷方向回弹变形强烈、扩容显著、脆性破坏特征明显;卸荷条件下岩石破坏具有较强的张性破裂特征,各种级别的张裂隙发育,其剪性破裂面追随张拉裂隙发展。基于试验认识,将卸荷条件下岩石的本构模型分为4段：弹性段、卸荷屈服段、峰后脆性段及残余理想塑性段;通过体积应变εv将Griffith和Mohr Coulomb屈服准则结合起来,建立卸荷条件下岩石的屈服准则,并在应变空间建立相应的卸荷非线性屈服段本构方程;运用应变软化理论,建立卸荷岩石峰后脆性段本构方程。 相似文献
10.
差异风化型危岩多形成于由砂岩和泥岩等软、硬岩性组成的互层陡倾岩质边坡中,其崩塌破坏属地质灾害中的常见形态。以普洱渡危岩高边坡为例,推导出差异风化型危岩岩腔后壁泥岩压应力随岩腔深度增加而增大的计算公式。据普洱渡危岩高边坡地形地貌和地质构造特征建立了两类4种差异风化型危岩力学模型：第1类为主控结构面贯通率等于1时的泥岩基座压裂破坏型和转动破坏型危岩;第2类为主控结构面贯通率小于1时的坠落型和倾倒型危岩。利用岩石强度理论推导出研究区砂岩的二次抛物线型摩尔强度包络方程,以极限平衡理论和摩尔强度理论推导了4种危岩体在自重、地震力和裂隙水压力共同作用下的崩塌破坏判别表达式,并由此反演出危岩体的临界崩塌边界方程,得出危岩体崩塌边界（岩腔深度、危岩体厚度和高度、主控裂隙深度）之间的关系,为现场预测和判别危岩体的稳定性和崩落时序提供简便可靠的依据。 相似文献
11.
We present a micro‐mechanical analysis of macroscopic peak strength, critical state, and residual strength in two‐dimensional non‐cohesive granular media. Typical continuum constitutive quantities such as frictional strength and dilation angle are explicitly related to their corresponding grain‐scale counterparts (e.g., inter‐particle contact forces, fabric, particle displacements, and velocities), providing an across‐the‐scale basis for a better understanding and modeling of granular materials. These multi‐scale relations are derived in three steps. First, explicit relations between macroscopic stress and strain rate with the corresponding grain‐scale mechanics are established. Second, these relations are used in conjunction with the non‐associative Mohr–Coulomb criterion to explicitly connect internal friction and dilation angles to the micro‐mechanics. Third, the mentioned explicit connections are applied to investigate, understand, and derive micro‐mechanical conditions for peak strength, critical state, and residual strength. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Richard J. Lisle 《Mathematical Geology》1992,24(5):455-461
Procedures are outlined for the selection of a least squares best-fit circle to data points defined by rectangular Cartesian coordinates. Equations are derived to allow fitting of circles centered on the x-axis as well as off-axis Mohr circles. These procedures are applicable to the estimation of second-order tensors such as stress and strain by means of Mohr's diagram. 相似文献
13.
Richard J. Lisle 《Mathematical Geosciences》1992,24(5):455-461
Procedures are outlined for the selection of a least squares best-fit circle to data points defined by rectangular Cartesian coordinates. Equations are derived to allow fitting of circles centered on the x-axis as well as off-axis Mohr circles. These procedures are applicable to the estimation of second-order tensors such as stress and strain by means of Mohr's diagram. 相似文献
14.
单砂体高部位油水倒置分布的成因机制 总被引：11，自引：1，他引：10
成藏地质条件的复杂多变控制了油水分布的复杂性和多样性,尤其是在低渗透油藏中。断层圈闭油藏和岩性油藏中存在一种类似的油水倒置分布样式,即由单砂体高部位向低部位,依次为水层、含油水层、油水同层、油层、油水同层、含油水层、水层。通过分析两种油藏类型中低渗透砂体储层高部位油水倒置的控制因素,探讨了油水倒置的两种成因机制。分析结果表明,断层圈闭为主的油藏中,造成油水倒置的主要原因是断层封闭性的历史性差异,其次是储集层物性和渗透率级差;而上倾尖灭砂体岩性油藏中,造成油水倒置的主要因素是储集层物性及其变化,尤其是储层层内非均质性。同时,分析结果进一步表明,油水倒置系统中,存在低电阻率油层。 相似文献
15.
Colin Flint 《GeoJournal》2000,51(3):145-156
This paper makes two contributions towards making a theoretically driven electoral geography a vital component of geography. First, a theoretical framework for the empirical analysis of elections is proposed that views elections as one component of the social construction of space while simultaneously illustrating how space structures electoral behavior. Second, the concepts of a geographic theory of voter mobilization need to be operationalized in such a way that space is an integral component of statistical analysis. The statistical concepts of spatial dependence and spatial heterogeneity are used to include electoral locales and the regionalization of voter mobilization in the analysis. The theoretical framework and statistical operationalization proposed are illustrated by a statistical analysis of the growth of the Nazi party vote in Baden between 1924 and 1932. 相似文献
16.
运用极摩尔圆法、张量分析法和应力取向分析法对内蒙亚干变质核杂岩的剪切作用类型进行了定量分析。相关韧性剪切带的运动学涡度值为 0.53-0.87, 表明相关的剪切作用为减薄型一般剪切。其间的差异,表明主期以简单剪切为主,递进变形过程中, 纯剪切组分增加, 这很可能与因晚期脆性断层引起的位移分解作用有关。同向伸展褶劈理的取向与剪切带边界的夹角既不等于两流脊间的夹角,也不等于其值之半,但可据以确定主应力方向,从而确定两流脊间的夹角和对应的运动学涡度 相似文献
17.
应用大地电磁测深勘查北京平谷盆地隐伏含水岩溶系统的结构 总被引：1，自引：0，他引：1
将大地电磁测深用于寻找深层地下水,在北京东部平谷盆地实施3条剖面25个测点,在资料分析过程中,对部分测点实施Mohr圆阻抗张量分解技术;在自动反演过程中,引入Rhoplus和Rebocc反演程序。通过对反演解释结果的分析,认为测区第四系地下水含量丰富,断裂构造及含水岩溶发育。对比3条剖面的电性分布特征,推测存在走向NNE的区域性断裂F1,其所经之处控制基岩中含水岩溶的发育;与F1相交的NW向次级断裂带控制了另一深部含水岩溶发育区,不同方向的含水岩溶发育区因断裂构造相通,呈现“网络”式的分布格局。 相似文献
18.
19.
本文综合应用研究区目的层段岩芯样品的各项分析测试资料,对储集砂岩的成岩作用和孔隙结构进行研究,揭示了枣园油田储集砂岩的成分成熟度和结构成熟度均较低;各组分含量变化大是造成储层成岩变化和孔隙结构复杂的因素之一。孔一、二段砂岩经历了压实、胶结、交代、溶解和自生矿物充填等成岩作用。孔一段上部孔隙类型以原生孔隙为主,孔隙和喉道发育、孔渗高,但孔喉分选差;下部原生和次生孔隙并存。孔二段主要是次生孔隙,孔喉细、分选差,孔渗性较孔一段上部差。 相似文献
20.
《Computers and Geotechnics》2006,33(4-5):275-277
Conventional slope stability analysis is usually based on the linear Mohr–Coulomb failure criterion utilizing the notion of safety factors with respect to shear strength, and one of the available slice methods. Failure criteria of most soils are not linear, and it is possible to show that this non-linearity has a very significant effect on calculated safety factors. The present work is based on a non-linear failure criterion, which appears to fit the experimental information better than Mohr–Coulomb. All slice methods utilize various kinematical and static assumptions, which cannot be rationally justified. The present work is based on rigorous variational approach to slope stability analysis, which does not employ any kinematical and static assumptions. Safety factors with respect to shear strength are useful abstractions, but physical significance of results based on them is clear only at failure when they are equal to 1 (at any other value of the safety factor with respect to strength results of the analysis correspond to fictitious material with a modified shear strength function). In the present note, we use the variational analysis in order to establish a simple analytical relation between safety factors with respect to strength and height. These two safety factors provide alternative measures for the stability of a given slope; but the safety factor with respect to height appears to have clearer physical interpretation. 相似文献