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1.
某滑坡蓄水后的三维稳定性数值分析 总被引：1，自引：0，他引：1
通过有限差分软件FLAC3D对滑坡进行了三维稳定性计算和分析,采用强度折减法计算出蓄水边坡的安全系数。计算结果表明:该滑坡在蓄水条件下,整体仍处于稳定状态,只是在相对较陡的滑坡体前缘和库水位淹没区,蓄水后可能会产生小规模失稳。边坡采用强度折减法计算的安全系数为1.20。 相似文献
2.
为深入探究水库水位变化对滑坡稳定的影响,以西南地区某库岸滑坡为例,在探明滑坡工程地质条件和成因机制的基础上,通过建立三维数值模型来分析流固耦合作用下库水位变化对库岸滑坡稳定性及滑动模式的影响。通过数值计算,获得水库天然状态、初期蓄水、水位上升和下降条件下滑坡体内塑性区分布和x方向位移变化情况。结合数值计算结果和滑坡实际变形破坏规律综合分析库水位变化对库岸滑坡稳定性的影响。分析结果显示,水库初期蓄水造成滑坡体变形开裂,使坡体处于不稳定状态;水位上升对滑坡稳定性影响较小,水位下降后滑坡稳定性大幅降低,极可能发生失稳破坏;水库蓄水后坡体滑动模式由推移式向牵引式转变。 相似文献
3.
卡拉水电站上田滑坡体稳定性分析及评价研究 总被引：1，自引：0，他引：1
[摘 要] 为了分析卡拉水电站工程区某滑坡体的稳定性,通过对其滑坡成因、地形地貌、地质构造、
岩土力学参数敏感性等内在因素分析可知,滑坡体随着坡面隆起和坡内扩容加剧,在外界作用下易导致
边坡失稳破坏;其层面与节理裂隙的不良组合为边坡变形失稳提供了边界,陡倾坡内的裂隙,为地下水
的入渗创造了条件;滑坡稳定性随着岩土力学强度参数的提高而增强。通过对降雨、水位升降和地震等
外在因素的敏感性分析可知,库水位骤升骤降对滑坡的稳定性影响较大;短期降雨影响较小,但时间增
长滑坡失稳概率增加;地震峰值对滑坡稳定性影响较为明显。同时根据分析结果对滑坡体进行了工况
及荷载组合,并对各工况组合进行了稳定性计算及评价,得出水位下降时滑坡稳定性处于极限状态,在
蓄水地震工况下失稳概率较大。 相似文献
4.
本文以德钦县住建局滑坡为研究对象，通过现场勘查和室内分析边坡岩土特征，重点针对德钦县住建局滑坡地质灾害产生的具体原因进行深入分析。利用极限平衡法，对边坡进行定性和定量的分析，结果表明：住建局滑坡成因主要为地形较陡、地层岩性较破碎、河流侵蚀切割和修路切坡；滑坡为中型浅层混合式土质滑坡，目前滑坡处于基本稳定状态，不利工况下滑坡可能发生整体滑移。 相似文献
5.
为了研究地下水渗流对崩坡积滑坡变形的影响，通过分析现场调查勘察资料，在研究该滑坡所处的地质环境条件、滑坡的形态特征和变形特征的基础上，探讨了该滑坡的形成机制，对比了地下水渗流对崩坡积滑坡和老滑坡的影响，并开展了数值模拟。取得的认识有:（1）地形地貌、地层岩性、大气降水、人类工程活动是该滑坡形成的主要原因。在这些因素共同作用下，滑坡最终失稳变形，过程中可能发生多次滑动，形成现今的堆积形态。（2）降雨引起的地下水渗流对该崩坡积滑坡稳定性和变形的影响是十分显著的。对于局部架空现象较严重的崩坡积组成的Ⅲ号滑坡体，雨水更易入渗进入坡体，地下水渗流对其稳定性和变形的作用十分明显；而对于优势通道较少的Ⅰ号和Ⅱ号老滑坡体，局部架空现象相对较差，地下水渗流对其稳定性和变形的作用不显著。（3）降雨时间和降雨强度与滑坡稳定性负相关。降雨强度较小时、一定时间内降水对滑坡稳定性影响不大，但降雨较大时，滑坡稳定性将快速降低。 相似文献
6.
大沟湾滑坡是瞿家湾滑坡群中相对高差最大的滑坡体, 洞坪水库蓄水后滑坡体产生了较大变形且变形机制表现出一定的特殊性.野外调查研究表明: 蓄水前该滑坡体稳定性良好; 蓄水至452m后, 滑坡后缘堆积体与基岩交界处产生贯通滑坡两侧冲沟的连续裂缝, 剪出口位于整个滑体中部580m高程附近, 由于下部坡体的抗滑作用而使整个坡体仍处于稳定状态; 蓄水至488m后, 从整个滑体前缘到570m高程附近又形成另一滑坡体, 与先前上部滑坡呈梯级分布, 分析得出大沟湾滑坡为上部牵引-下部推移的复合式滑坡, 两个滑坡共同作用导致整个滑体发生明显变形.分析并利用FLAC3D模拟再现整个变形过程, 对滑坡体变形破坏机制做出了很好解释. 相似文献
7.
库水位下降条件下和平广场滑坡稳定性分析 总被引：1，自引：0，他引：1
首先介绍了和平广场滑坡体的地质条件,然后用FLAC3D建立了三维计算模型,对现状条件下及三峡水库库水位下降时的地下水进行了计算,并对滑坡的稳定性进行了分析,得出了不同工况滑坡体应力场分布规律及塑性区分布范围.结果表明:在现状条件下,滑坡体总体上处于稳定状态,但在滑坡体后部及中前部基岩面较陡区域附近出现一定程度的塑性区;三峡水库的运营不会危及滑坡整体的稳定性,但在库水位下降的过程中,由于滑坡体前部基岩面较陡,地下水的渗透压力增大,导致下滑力增大,从而可能使其前缘局部地段产生破坏. 相似文献
8.
马王山滑坡位于马王山北坎、市汽车零件厂南侧，形成的主要因素是斜坡体内广布易软化的倾斜倾角较坡角小的泥质粉砂岩强风化层、季节性的强降雨、以及人为的切坡活动．呈现切层、推移式发生机理．滑坡防治不仅要考虑滑坡体本身的稳定，而且还要考虑滑坡区前缘市汽车零件厂冲压车间和配电房的安全。 相似文献
9.
金山坡板梁状平推式滑坡成因机制分析 总被引：1，自引：0，他引：1
以四川省泸州市纳溪区金山坡滑坡为典型案例,通过详细调查和分析解剖,提出板梁状平推式滑坡的成因机制。板梁状平推式滑坡在平面上呈扁长矩形,纵向长度小于横向宽度,剖面上呈板梁状。该类滑坡主要发生于由近水平巨厚层砂岩和薄层泥岩构成的斜坡陡崖附近,坡内存在一组平行于坡面的长大陡倾结构面。在强降雨条件下,雨水迅速充填平行于坡面的张裂缝,至某一临界高度后,强大的静水压力将外侧岩体整体平推出去,形成平推式滑坡,此后随着裂缝内水头的骤降,滑体很快自行停止滑动。在较系统地调查并研究形成该滑坡所具备的岩性条件、坡体结构条件、裂缝储水条件以及强降雨触发条件的基础上,针对板梁状平推式滑坡的后续变形破坏模式,提出加强截排水,采用锚索和抗滑桩的工程治理措施。 相似文献
10.
三峡库区秭归县头道河Ⅱ号滑坡特征及稳定性评价 总被引：2，自引：0，他引：2
针对三峡库区秭归县头道河Ⅱ号滑坡现状条件下的明显变形迹象,对该滑坡进行了综合的分析和研究,并详细介绍了该滑坡的地质背景及滑坡特征。采用剩余推力法,对滑坡体在各种不同工况下的稳定性作了分析,并对滑坡体在三峡水库蓄水以后的稳定性作了合理评价。结果表明,滑坡体在目前状态下基本稳定,三峡水库蓄水以后．将对滑坡体稳定性产生较大影响,极有可能导致滑坡体失稳,据此结合工程实际提出了治理高程175m以上滑体和土体为主,同时布置抗滑桩等的防治措施及建议。 相似文献
11.
The possible application of a Rindler type reference frame for studies of physical processes near the horizons of black and white holes is considered. New similar reference frames inside black and white holes in the region T of a Kruskal wormhole are introduced. 相似文献
12.
A supernova explosion in a close binary system in which one of the components is a compact magnetized object (neutron star or white dwarf) can form a narrow “tail” with length l t ～109 cm, width h t ～108 cm, and magnetic field B t ～106, due to the resulting shock wave flowing around the magnetosphere of the compact object. The energy released by the reconnection of magnetic field lines in this tail can accelerate electrons to relativistic speeds (γ≈104), creating the conditions required for powerful synchrotron radiation at energies from hundreds of keV to several MeV, i.e., for a gamma-ray burst (GRB). The duration of this radiation will depend on the power of the shock that forms during the supernova. If the shock is not sufficiently powerful to tear off the magnetosphere tail from the compact object, the duration of the GRB will not exceed l t /V A ≤1 s, and the conditions necessary for an “afterglow” at softer energies will not arise. If the shock is more powerful, the tail can be torn from the magnetosphere, forming a narrow ejection, which is perceived in its relativistic motion toward the observer(Γ～104) as an afterglow whose duration grows from tens of seconds at gamma-ray energies to tens of days in the optical. This may explain why afterglows are observed only in association with long GRBs (T 90>10 s). Very short GRBs (T 90<0.1 s) may be local, i.e., low-power, phenomena occurring in close pairs containing compact, magnetized objects, in which there is again an interaction between the magnetosphere of the compact object and a shock wave, but the shock is initiated by a flare on the companion, which is a red-dwarf cataclysmic variable, rather than by a supernova. 相似文献
13.
Victor Ryzhik 《Computational Geosciences》2007,11(1):1-8
Spreading of a non-aqueous phase liquid (NAPL) denser than water (DNAPL) lens (mound) in the unsaturated zone of double-porosity
aquifer above an impervious plane boundary is investigated. The double-porosity aquifer is conceptualized as a fracture network
surrounding pervious blocks. Vertical gravity equilibrium is assumed to prevail in each one of the two media, fractures and
blocks. Through vertical integration, two coupled partial differential equations for the DNAPL content in each medium are
obtained. The mass exchange rate between high- and low-permeability media is considered as a function of NAPL content. The
dominant effect is gravity, whereas capillary forces are negligible. Analytical solutions for one-dimensional and axisymmetric
problems of mound spreading are obtained. 相似文献
14.
M. Yu. Reshetnyak 《Astronomy Reports》2016,60(2):294-305
The dependences of the magnetic-field strength, variations of the magnetic field, and the multipole level on the amplitudes of the α and ω effects are considered using a two-dimensional model for a Parker dynamo in a spherical layer. Calculations have been carried out for both traditional spatial distributions of α and ω and geostrophic regimes obtained from three-dimensional modeling of thermal convection. Two-dimensional distributions of the dynamo-wave velocities in the zone where magnetic field is generated are presented. Comparisons with the solar and planetary dynamos are considered. 相似文献
15.
An algorithm for determining if any given point,P, on the surface of a sphere is located inside, outside, or along the border of an arbitrary spherical polygon,S, is described. The polygon is described by specifying coordinates of its vertices, and coordinates of some pointX which is known to lie withinS. The algorithm is based on the principle that an arc joiningX andP will cross the border ofS an odd number of times ifP lies outsideS, and an even number of times ifP lies withinS. The algorithm has been implemented as a set of FORTRAN subroutines, and a listing is provided. The algorithm and subroutine package can be used with spherical polygons containing holes, or with composited spherical polygons. 相似文献
16.
K. Z. Andrawes R. R. Al-Omari W. M. Kirkpatrick 《Geotechnical and Geological Engineering》1996,14(3):227-236
The effect of a smooth rigid stratum, located beneath a dense sand layer, on the bearing capacity and settlement of surface and shallow strip footings is investigated using an advanced experimental model. A theoretical analysis is presented for the bearing capacity of surface footings. The results indicate that the bearing capacity reaches a minimum value at a specific sand-layer thickness. Any increase in the layer thickness above this value causes an increase in the bearing capacity up to that corresponding to a continuous media.Notation
H=
thickness of the sand layer
-
B=
foundation width
-
N
q and N
=
bearing capacity factors for a semi-infinite layer
-
N
qs and N
s=
bearing capacity factors for a finite layer
-
H
o
/B=
limiting depth
-
D
r=
relative density
- =
angle of soil internal friction
-
M=
model width
-
D=
depth of surcharge
-
q=
bearing stress, pressure applied on the footing
-
q
u=
bearing capacity
- =
unit weight of sand 相似文献
17.
The focus of this contribution is to develop a complex variable function method to solve the two-dimensional scattering of plane waves by a lined cylindrical cavity in the poroelastic half-plane. The poroelastic half-plane is based on Biot’s dynamic theory, and the governing equations are solved by reduction to three Helmholtz equations. The lining structure can be treated as an elastic material and decoupled into two Helmholtz equations. Here, the large circle assumption is applied to simulate the half-plane boundary. By using appropriate boundary conditions and continuity conditions, the unknown coefficients in the potentials can be determined. Selected numerical results are presented in this paper. 相似文献
18.
Summary Any rock may be regarded as an aggregate of mineral species frequency distributions, thus opening up a new method of analyzing the problems of the nature of these discrete distributions.Based on theorems in mathematical probability, a subrock sample is defined as a probability sample under the conditions that every mineral species' distribution function in this subrock converges probabilistically to one and the same distributions the nature of which is immaterial at this point.For obvious reasons, the situation is excluded if the sample size approaches infinity, i.e., Chebyshev's theorem (Chebyshev, 1867). 相似文献
19.
20.
Strain analysis of a shear zone in a granodiorite 总被引：1，自引：0，他引：1
A ductile shear zone in a late Precambrian granodiorite, from the Rouergue (southwest part of the French Massif Central) has been studied.A single episode of deformation is responsible for the formation of a foliation and a well-defined lineation which are localized into an elongated zone, a few decimeters wide.The strain features can be attributed to a simple-shear mechanism (Ramsay and Graham, 1970), so that the main parameters of the deformation are defined.At stages of increasing deformation, the quartz isotropic sub-fabric of the undeformed host rock is progressively transformed into an anisotropic fabric composed of a single oblique girdle while the subgrain size progressively decrease and the dislocation density remains constant. It is suggested that the gliding planes of quartz are the basal plane (0001) and a predominant prismatic plane 101̄0 the slip directions may be a for both glide-planes.The results obtained in this investigation provide a basis for a high voltage electron microscope (H.V.E.M.) study which shows that the fabrics development may be related to dislocation processes. The difference of strain rates in the host rock and in the shear zone is calculated from the dislocation microstructures. 相似文献