共查询到20条相似文献,搜索用时 968 毫秒
1.
Rennie B. Kaunda Ronald B. Chase Alan E. Kehew Karlis Kaugars James P. Selegean 《Environmental Earth Sciences》2010,60(7):1545-1558
A back propagation artificial neural network approach is applied to three common challenges in engineering geology: (1) characterization
of subsurface geometry/position of the slip (or failure surface) of active landslides, (2) assessment of slope displacements
based on ground water elevation and climate, and (3) assessment of groundwater elevations based on climate data. Series of
neural network models are trained, validated, and applied to a landslide study along Lake Michigan and cases from the literature.
The subsurface characterization results are also compared to a limit equilibrium circular failure surface search with specific
adopted boundary conditions. It is determined that the neural network models predict slip surfaces better than the limit equilibrium
slip surface search using the most conservative criteria. Displacements and groundwater elevations are also predicted fairly
well, in real time. The models’ ability to predict displacements and groundwater elevations provides a foundational framework
for building future warning systems with additional inputs. 相似文献
2.
Steve J. Hodgetts Brendan C. O’Kelly Matthew J. Raybould 《Geotechnical and Geological Engineering》2007,25(6):705-715
A landslip occurred near the village of Stanton Lees, Derbyshire, UK, in November 2000 following a prolonged period of heavy
rainfall. The slip resulted in the gradual, progressive down-slope movement of a steep embankment that was supporting an existing
gabion retaining wall and a minor road which was subsequently closed to vehicular traffic. This paper describes the site;
the sequence of events leading up to the start of the landslide; an interpretation of the ground conditions and onsite monitoring
data; and the engineering works carried out in order to stabilise the slip and return the road to serviceability. The landslip
occurred due to the superficial deposits moving over the weathered bedrock after the groundwater levels had been elevated
following a prolonged period of heavy rainfall. A stability analysis indicated that the embankment was at a state of limiting
equilibrium and its factor of safety on slope instability was found to be particularly sensitive to fairly minor changes in
the groundwater levels. The remedial works replaced the existing gabion wall with a new cantilevered, bored pile retaining
wall that comprised two rows of piles (600-mm in diameter), which were staggered in plan arrangement. 相似文献
3.
本文利用新的有限元方法研究了铲状正断层带在非均匀应力场下错动引起的位移场和应力场。研究发现:① 铲状正断层错动引起的断层面上的最大错距不是发生在地表,而是发生地表下面断层的中部;② 地表面最大水平位移和垂直位移都不是发生在地表断层上,而是发生在偏离断层一定距离的地方;③ 铲状正断层错动会在地表附近产生两个破裂区,一个在地表断层附近,一个在远离断层的上盘地表附近,这两个区与野外观测到的次生正断层区一致;④ 断层错动的应力降在断层内不是均匀的,最大值也是位于断层中部。 相似文献
4.
V. K. Gahalaut P. K. Gupta R. Chander V. K. Gaur 《Journal of Earth System Science》1994,103(3):401-411
We estimate the distribution of slip in the dip section of the causative fault for the 1905 Kangra earthquake by applying
the minimum norm inversion technique to differences in pre- and post-earthquake levelling data collected along the Saharanpur-Dehradun-Mussoorie
highway. For this purpose it is assumed that the causative fault of the 1905 Kangra earthquake was planar with a dip of 5°
in the northeast direction and that it had a depth of 6 km at the southern limit of the Outer Himalaya in Dehradun region.
The reliably estimated maximum slip on the fault is 7.5 m under the local northern limit of the Outer Himalaya. Using the
inverted slip distribution we estimate that the maximum permanent horizontal and vertical displacements at the surface due
to the Kangra earthquake were about 4 m and 1.5m respectively. The maximum transient displacements at the surface should have
exceeded these permanent displacements. These estimates of maximum slip on the causative fault and the resultant maximum permanent
and transient displacements at the surface during the Kangra earthquake may be taken tentatively as being representative of
the great Himalayan earthquakes. 相似文献
5.
传递系数法假定条块作用力方向与上一条块底滑面平行。相关文献指出基于这样的假设可能导致计算结果偏大,偏于不安全。基于此,对条间作用力方向角进行修正:假定条间力方向角为上一条块底滑面倾角与未知常数λ(推力方向修正系数)的乘积,通过考虑边坡整体力矩平衡求解修正系数,进而求得边坡稳定系数,对传递系数法进行改进。通过经典算例及工程实例验算,结果表明,改进法计算结果较传统传递系数法更精确,物理过程更合理,能够满足工程精度要求。 相似文献
6.
地下矿产资源的开采会引发地面塌陷,这已成为严重制约矿区可持续发展的重要因素。其主要表现形式有:塌陷盆地、塌陷坑、地裂缝、滑坡崩塌等,并引发道路污染和道路改线及居民地和水系的变化。在矿山开发多目标遥感调查与监测过程中,这种地质灾害现象较为突出。本文在总结了地面塌陷的主要类型及其特征的基础上,对塌陷地的遥感识别方法进行了分析和研究。 相似文献
7.
圆弧滑动有限元土坡稳定分析 总被引:13,自引:0,他引:13
提出一种基于有限元应力变形计算的边坡稳定分析方法,仍假定滑动面形状为圆弧形,有限元网格由一组同心圆作为纬线,一组竖向线为经线构成。对两相邻圆弧线所夹的弧形带分析滑动力和抗滑力,建立平衡方程,确定安全系数,其中小值安全系数对应的弧形带为可能的滑动带。变化圆心位置用优选方法寻找最小安全系数对应的圆心,从而得出真正的滑动面。算例分析表明,该方法计算所得安全系数与Bishop法接近,是合理的,其突出优点是由有限元计算直接得出滑面上的应力,而不须作近似的插值处理,因而应力更准确。该方法可以考虑土的非线性变形特性,也更符合土的实际情况。此外,用有限元计算得出位移,亦可将稳定分析和变形联系起来,为现场通过位移监测来估计边坡的稳定性提供了可能性,同时也为膨胀土边坡的稳定分析中考虑膨胀性的影响提供了可能性。 相似文献
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İ Tiryakioğlu B. Aktuğ C. Ö. Yiğit H. H. Yavaşoğlu H. Sözbilir Ç Özkaymak 《Geodinamica Acta》2018,30(1):1-14
Greek-Turkish boundary near the cities Kos and Bodrum has been shaken on July 20, 2017 by a Mw6.6 earthquake. The mainshock is located offshore and did not generate an on-land surface rupture. Analyzing pre- and post-earthquake continuous/survey-type static GPS observations, we investigated co-seismic surface displacements at 20 sites to characterize source parameters and slip-distribution of the mainshock. Fault plane solutions as well as co-seismic slip distribution have been acquired through the inversion of co-seismic GPS displacements modeling the event as elastic dislocations in a half space. Fault plane solution shows a southward dipping normal-type fault segment extending a depth down to ~12 km, which remains within the brittle upper crust. Results from the distributed slip inversion show that the mainshock activated a ~65 km fault section, which has three high slip patches, namely western, central and eastern patches, where the coseismic slips reach up to 13, 26, and 5 cm, respectively. This slip pattern indicates that the pre-earthquake coupling, which is storing the slip deficit, occurred on these three patches. 相似文献
11.
Finding the critical slip surface and estimating the landslide volume are of primary importance for slope seismic design. However, this may be difficult due to the uncertainty of ground motions. To address this problem, a new method for calculating uncertainties is recommended in this paper, especially for the critical slip surface and landslide volume under random earthquake ground motions. Firstly, a series of intensity–frequency nonstationary random earthquake ground motions were generated based on an improved orthogonal expansion method. A given number of potential slip surfaces were set in a soil slope. Subsequently, the factor of safety (FOS) of each slip surface for all ground motions was calculated and the minimum FOS curves were obtained. It was found that the critical slip surfaces and failure times are uncertain under different earthquakes. The Monte Carlo method was used to verify the accuracy of probability density evolution method (PDEM), and the results of the PDEM and the Monte Carlo method are consistent, meaning that the PEDM has higher computational efficiency. Moreover, the distributions of earthquake-triggered landslide volume and landslide depth were analyzed by considering equivalent extreme events. Both landslide volume and depth exhibit a normal distribution for a homogeneous soil slope. The framework of this study is meaningful for slope seismic design in engineering, for example, the location of critical slip surface can be used for slope reinforcement, and the distribution of sliding volume can be used for disaster assessment. 相似文献
12.
在分析区域地质环境背景基础上,总结出唐山地区主要公路工程地质灾害有崩塌、滑坡、泥石流、采空塌陷、地面沉降、地裂缝和砂土液化,其中崩塌、滑坡、泥石流为主要灾害。并根据灾害发育特征提出了相应的防治措施。 相似文献
13.
陡倾断层上下盘开挖引起地表变形的数值模拟分析 总被引:1,自引:0,他引:1
考虑地下开挖区与断层相对位置关系,采用简化数值模型对陡倾断层上下盘开挖引起的地表变形特征进行了数值模拟。结果表明,当断层位于地下开挖引起地表变形的压缩区且开挖区位于下盘时,地表出现不连续变形的可能性小;当断层位于地下开挖引起地表变形的压缩区且开挖区位于上盘时,随下向开挖进行地表断层处裂缝有减小趋势;而当断层位于地下开挖引起的地表变形拉张区时,断层出露处水平拉张明显,表现为拉张裂缝,随下向开挖深度增加、规模增大,不论开挖区位于上盘还是下盘,极可能导致地表出现正断层式的错动. 相似文献
14.
结合铜川市区自然地理地貌条件,分析了市区所属黄土坡地、矿区高陡山体边坡下煤层开采引发的环境岩土工程问题。对矿区高陡山体边坡崩塌环境灾害的影响因素进行了分类分析;对矿区开采与地表移动变形和高边坡崩塌灾害演化形成的机理进行了分析。结合实例,应用CEPDF程序模拟计算,研究结果对于铜川市区条件下高陡山体边坡灾害防治有一定参考价值。 相似文献
15.
京张高铁怀来段位于怀涿、延矾盆地复合部位,盆地内土体工程地质特性的差异及隐伏断裂稳滑活动产生的地面沉降无疑会威胁京张高铁的安全运行。依据工程地质钻孔及地球物理探测资料,构建跨活动断层地基土体二维地层结构模型,通过数值模拟手段开展考虑断层效应的高铁列车动载荷对地面沉降的影响机理研究。研究表明:列车动荷载主要影响50 m深度范围内的土体,随车速增加动荷载造成的土体竖向位移降低,随车重增加竖向位移增加;在列车动荷载和断层滑移双重作用下,随深度增加,土体竖向位移以受列车动荷载影响为主转为以断层滑移影响为主,50 m以下土体竖向位移全部由断层滑移所致,且紧邻断层两侧距离相同位置上盘土体竖向位移大于下盘。 相似文献
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Traditional investigation methods for studying landslide and slope stability is concentrated on studying the present and original
geometry of slope, geological cross-section, position of water table and shear strength parameters. It is of prime importance
to determine the thickness of slipped ground and the slope of the slip surface. The depth is usually estimated from trial
pitting, trenching and drilling boreholes. By using advanced non-invasive geophysical techniques engineers can get a representative
picture of hidden subsurface condition with less disruption than using traditional investigation methods like coring, boring
and sampling. 相似文献
18.
Displacement profiles (normalized displacement vs normalized distance from the point of maximum displacement) have been plotted for 34 horizontal radii from 25 normal faults with maximum displacements ranging from 1.0 to 37.5 m. The composite displacement profile for these faults, when corrected for systematic inaccuracies of the data, is significantly different from the theoretical slip profile for a single seismic slip event. The integration of slip displacement profiles of many slip events on a growing fault shows that a steady-state displacement profile will be established. This theoretical displacement profile is similar to the composite profile derived from the fault data. Analysis of displacement data from 488 fault traces, which do not necessarily pass through the point of maximum displacement of their respective faults, shows that although displacement measurements are strongly influenced by ductile drag the theoretical distribution can still be identified in the data. Although the slip distribution on a fault during a single slip event, or during a period of stable sliding, is not simply related to the distribution of cumulative displacement on the fault, a knowledge of both characteristics places firm constraints on fault growth models. 相似文献
19.
Mohr-Coulomb准则下基于滑动面深度的边坡参数反分析方法 总被引:1,自引:0,他引:1
利用上限定理与强度折减法,提出了一种新的边坡反分析方法。该方法基于边坡的滑动面形状,不需要位移、应力等监测数据。分析边坡的临界滑动面位置与强度参数的关系,可以发现,当边坡的几何形状、土体重度以及孔隙水压力分布确定,则临界滑动面的形状只与土体黏聚力c、内摩擦角φ的关系式c/tanφ有关,并在此基础上引入边坡的无量纲系数c,λcφ。利用极限分析上限定理与强度折减法,得到了边坡临界滑动面方程,提出了其深度的计算公式,建立了边坡c,λcφ值与滑动面深度的关系。通过已有边坡的反分析实例,验证了方法的正确性和有效性。 相似文献
20.
临界滑动面一方面是与岩体结构面和坡面的组合关系有关,另一方面与荷载大小及位置有关。三维条件下,均质岩高边坡的破坏机理比较复杂,临界滑动面的判定较为繁琐。本文基于应力影响系数法对荷载作用下对均质岩高边坡三维临界滑动面形态及位置进行初步判别,研究各因素变化对临界滑动面分布形态的影响,结果表明:荷载作用下均质岩高边坡空间临界滑动面主要发生在基础前侧区域,约为一不规则楔体,楔体尺寸与桥基尺寸、坡度及桥基距离有关,其中桥基距离影响最大,荷载强度对滑动面形态无影响。桥基荷载作用下均质岩高边坡临界滑动线范围随桥基尺寸、桥基距离增加而增大,随坡度增加,临界滑动线长度减小,深度增大。本文提出桥基荷载作用下均质岩高边坡临界滑动面范围确定公式,即:均质岩高边坡破坏长度Pw=08444L-05098+05759S+693716,破坏深度Ph=01148L+0171B+11725+00733S-5719。 相似文献