共查询到17条相似文献，搜索用时 125 毫秒
1.
对数正态分布下边坡稳定性二元指标体系研究 总被引：2，自引：0，他引：2
安全系数不能考虑边坡系统中实际存在的不确定性,可靠性理论缺乏丰富的工程实践经验,因此,将工程实践经验丰富的安全系数与先进的可靠性理论相结合,建立传统安全系数与可靠性相耦合的二元评价体系具有重要的理论意义和应用价值.设安全系数服从对数正态分布,取系列的最大可能安全系数（中值安全系数）和变异系数,计算得到最大可能安全系数及在不同变异系数下的破坏概率Pfo从而可由最大可能安全系数和可靠性（R=1-Pf）共同度量边坡的稳定性.将最大可能安全系数与边坡可靠性相乘,对最大可能安全系数进行折减,得到边坡可靠的安全系数.根据折减后安全系数的极限状态,可计算出不同最大可能安全系数的临界变异系数和临界破坏概率.根据不同最大可能安全系数及它的临界破坏概率,绘出边坡稳定性分区图,并建立安全系数和破坏概率相结合的边坡稳定性判别的二元指标体系.文中提供了小样本条件下,利用3倍方差原理估计参数方差的计算方法,并给出了边坡稳定性二元指标体系的研究实例. 相似文献
2.
《山地学报》2016,(5)
以兰州九洲开发区某边坡为例,采用Slide软件中的Sensitivity Analysis模块,对边坡进行敏感性分析,得出素填土a的重度和粘聚力是影响稳定性的主要因素,而其他岩土体的物理力学性质对计算结果影响不大;利用Probabilistic Analysis模块,进行了基于Monte-Carlo方法的安全系数与可靠度计算,评价了该边坡的稳定性,并与确定性计算结果进行了对比。结果表明:尽管安全系数基本一致,但从破坏概率来说,该边坡在自重状态下,坡体处于稳定状态,破坏概率最大为0.4%;在暴雨工况下,坡体均处于不稳定状态,破坏概率最小为70.3%;而在地震作用下,东段和南段的部分仍可稳定,破坏概率极小,仅为2.7%,评价结论更加可靠和直观,有利于边坡治理方案的优化设计。 相似文献
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强度再生效应在大型滑坡稳定性评价中的应用 总被引：2，自引：2，他引：0
通过大量现场调查、室内外试验及计算等研究的基础上,揭示了只要具有一定滑体厚度的滑带土,沿滑面具有强度再生效应。利用该观点,结合滑坡破坏特征,滑带土的物质组成及其赋存环境条件,对滑面强度参数的选取及其对稳定性的影响进行了详细探讨,该研究为滑坡滑面强度参数的选取提供了重要的理论依据。 相似文献
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边坡稳定性分析的可靠度方法 总被引：13，自引：4，他引：9
通过边坡破坏概率与安全系数的比较分析,提出基于概率方法的可靠性分析的必要性;同时从边坡可靠度指标β的几何定义出发,建立马氏距离表达式,并对其结果的可行性进行了验证。 相似文献
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《山地学报》2015,(6)
关于开挖对阶梯型边坡稳定性及其潜在滑动面位置的影响,目前还缺乏系统研究。以二阶阶梯型均质挖方边坡为研究对象,利用基于有限元应力状态的边坡稳定性分析方法,分别对不考虑开挖效应和考虑开挖效应两种条件下阶梯型边坡的稳定性及其潜在滑动面特征进行了对比,同时对开挖强扰动区的分布特征进行分析。研究结果表明:1.与不考虑开挖效应时计算的边坡安全系数相比,考虑开挖效应后计算得到的边坡安全系数偏小;2.开挖对阶梯型边坡的整体安全系数及其潜在滑动面位置的影响较小;3.在阶梯型均质挖方边坡的设计中,其平台宽度宜大于其上下级坡高平均值的0.5倍,上下级边坡的坡高比宜控制在1~2范围,且下级边坡的坡率小于上级边坡坡率时更有利于边坡的整体稳定。 相似文献
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地震作用下顺层岩质边坡稳定性的拟静力分析 总被引：2，自引：0，他引：2
通过对顺层岩质边坡的受力分析,应用极限平衡理论和Mohr-Column准则,按照Bishop关于边坡稳定性安全系数的定义,推导出在爆破震动载荷作用下,用于判别顺层岩质边坡稳定性的计算方法。研究结果表明垂直向下、水平指向坡外的爆破荷载以及两者的联合爆破荷载对边坡稳定性影响最大,尤其是后两者;水平指向坡外、垂直向下爆破荷载拟静力系数分别与边坡稳定性安全系数间呈负指数关系和S曲线关系;从动荷载拟静力系数0起,爆破震动水平指向坡外、垂直向下动荷载拟静力系数每增加0.05,有层裂长度的顺层边坡安全系数分别减少7.79%-10.67%、1.28%-1.98%,无层裂的顺层边坡安全系数分别减少7.61%-10.55%、1.47%-2.29%。同时,爆破震动产生的层裂长度、边坡长度以及联合爆破荷载的方向对顺层边坡稳定性也有影响。 相似文献
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对国道321线七宝莲边坡的气候、地质、地貌、水文等条件进行了综合分析，认为该边坡是潜伏着危险的不稳定边坡，其中地质构造、岩体结构、地表水和地下水作用是边坡变表破坏的主要影响因素，建议采用预应力框架挡土墙对边坡进行加固的防护措施。 相似文献
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高地震烈度区堆积体边坡动力响应时程特征分析 总被引：10，自引：0，他引：10
考虑到在地震过程中,工程边坡的动安全系数最小值出现在某一瞬间,而用这个值评价边坡在地震荷载作用下的抗滑稳定性不合适宜。在简单分析地震荷载作用下边坡稳定性评价的主要方法及差异基础上,介绍了地震动力响应时程分析法的基本原理和计算过程,明确指出了边坡动力稳定分析时应注意的边界条件、材料参数等问题,建立了评价动力稳定性的有限元应力法表达式。基于地震动力时程反应,结合金安桥水电站库岸堆积体边坡工程,用动力有限元计算获得了边坡的动力响应在空间的变化规律(包括动应力和加速度等)和整体稳定性,计算成果合理地评价了其稳定性。 相似文献
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基于基坑边坡支护设计的现状,本文主要以工程实例为基础,探讨了在基坑边坡支护设计中,地下连续墙及水泥土搅拌桩等支护形式由于岩土参数选取的不同所得到的不同优化,以及选取岩土参数的不同计算限值所对应安全系数,最后建立基坑支护设计中岩土参数选取模型,通过强度理论方面进行论证和实际施工检验,证明本文中所建立的模型的适用性。 相似文献
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采用工程地质钻探、物探、地质测绘及室内试验等技术方法探讨飞鹅山Ⅲ号滑坡形成机理与防治技术。结果表明：1）滑坡体主要岩性为泥质粉砂岩,飞鹅山滑坡属于新形成的深层中型牵引式滑坡,在平面上呈圈椅状。2）滑坡属于双层滑面滑坡,主滑面以中型深层滑坡为主,主滑体上部发育中型中厚层滑坡。3）滑坡产生的原因为：①泥质粉砂岩倾向与坡向基本一致,且岩层倾角为中等倾角;②人工开挖使坡脚形成高陡临空面,抗滑力大为降低;③雨水沿层面及节理裂隙入渗至坡体深部,大大增加岩土体容重,同时泥质粉砂岩遇水软化,抗剪强度显著降低。4）结合该滑坡区地质环境条件,采用坡面削坡+锚杆（索）+格构梁+双排预应力锚拉抗滑桩+三维网植草绿化+截排水+毛石挡墙的综合治理方法进行防治,监测结果显示该滑坡变形及位移已得到有效控制,整治效果良好。 相似文献
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The deformation and strength characteristics of roadbed slope under seismic loading in permafrost regions are simulated numerically. The seismic response of roadbed at different positions and inclinati... 相似文献
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Jun'ichi Fukuda Shin'ichi Miyazaki Tomoyuki Higuchi Teruyuki Kato 《Geophysical Journal International》2008,173(1):25-48
We have developed a new geodetic inversion method for space–time distribution of fault slip velocity with time-varying smoothing regularization in order to reconstruct accurate time histories of aseismic fault slip transients. We introduce a temporal smoothing regularization on slip and slip velocity through a Bayesian state space approach in which the strength of regularization (temporal smoothness of slip velocity) is controlled by a hyperparameter. The time-varying smoothing regularization is realized by treating the hyperparameter as a time-dependent stochastic variable and adopting a hierarchical Bayesian state space model, in which a prior distribution on the hyperparameter is introduced in addition to a conventional Bayesian state space model. We have tested this inversion method on two synthetic data sets generated by simulated aseismic slip transients. Results show that our method reproduces well both rapid changes of slip velocity and steady-state velocity without significant oversmoothing and undersmoothing, which has been hard to overcome by the conventional Bayesian approach with time-independent smoothing regularization. Application of this method to transient deformation in 2002 caused by a silent earthquake off the Boso peninsula, Japan, also shows similar advantages of this method over the conventional approach. 相似文献
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A finite difference two-dimensional model with Hooke–Mohr–Coulomb properties and topography derived from the DEM are used to reproduce the La Clapière landslide. The principal factor defining the gravity-driven destabilization of the model is a gradual reduction in the cohesion. This reduction simulates a degradation of the material properties with time because of weathering/alteration processes. The inelastic deformation, fracturing, and faulting first occur at mountain scale and results in normal fault formation causing crest sagging. Later, the failure process is concentrated in the lower part of the slope and leads to the formation of a localized fault subparallel to the slope surface at a depth of ca. 100 m. This corresponds to the initiation of the La Clapière landslide and its propagation upslope. A slow crest sagging continues during the whole model evolution. 相似文献
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Gbor Újvri Gyula Mentes Lszl Bnyai Jnos Kraft Attila Gyimthy Jnos Kovcs 《Geomorphology》2009,109(3-4):197-209
The banks of the River Danube are one of the most susceptible areas to mass wasting in Hungary. In 2007, a large slump began to develop along the Danube at Dunaszekcső and jeopardized properties on land and navigation in the river. Several factors such as geological, hydrogeological and morphological conditions, recurrent flooding and erosion by the Danube led to a gradual development of the large rotational slide. Slope failure has been monitored using GPS, precise levelling techniques and tiltmeters since October 2007. The expected location of the maximum lateral displacement and extrusion was indicated by GPS measurements from the middle of November 2007. The main phase of the slope failure evolution, i.e. the rapid movement on 12 February 2008 was indicated by accelerated tilting of the southern moving block prior to slumping. Small rise of the relatively stable part of the slope was measured after the rapid movements, which may be explained either by the elastic rebound along the slip surface, or by the intrusion of some plastic material into the lower section of the slope.Comparison of geodetic datasets and field observations with the timing of rainfall and water level changes of the Danube suggested that hydrological properties (subsurface flow processes, soil physical properties, infiltration, and perched water table) were primarily responsible for initiation of the studied slump. A model of slope failure evolution is proposed here based on the monitoring and field observations. 相似文献
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不稳定斜坡危险度的判别 总被引：1，自引：0，他引：1
为判别不稳定斜坡的危险度,在斜坡表面的变形迹象、斜坡本身的内部条件及外界的触发因素中,分出12项定性定量判别指标,它们各自有因子判别值Xj(i为判别指标的编号,1—12;j为因子判别值等级编号,1—6)。把各判别指标的因子判别值Xj叠加并予以综合后,便得叠加因子判别值Y=sum from 1 to N(Xj/N)(N为判别指标的数目,至少取6个),再查表13,定出不稳定斜坡危险度D。 相似文献
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A method developed by Røste et al. , which discriminates between layer thickness and velocity changes, is tested on pre-stack time-lapse seismic ocean bottom cable (OBC) data from the Valhall Field. A key parameter in this discrimination process is the dilation factor, α, which is the relative velocity change divided by the relative thickness change within a given layer. The high quality and good repeatability of the OBC data enables us to estimate α with a reasonable accuracy for α-values between 0 and −5. For α-values below −5, complementary information, like for instance geomechanics is required. For the top reservoir horizon we estimate a maximum subsidence of 0.50 m ± 0.29 m and a corresponding velocity decrease for the sequence from the seabed to the top reservoir of 2.0 m s−1 ± 0.40 m s−1 .
Time-lapse distortion patterns with characteristic time-shift versus offset signatures are observed. The positions and vertical extents of the distortion zones are determined from ray path considerations and modelling. The distortion zones correlate with buried faults, indicating that a (time-lapse) distortion zone might be produced by a localized slip in a fault zone. We present an extended method which allows for vertical (in addition to lateral) variations in the relative thickness and velocity changes. This method can be viewed as a simplified version of time-lapse tomography, but involving fewer unknown parameters, giving more stability to the estimated changes in thickness and velocity. Using this technique, we are able to estimate α for positions with localized time-lapse distortions. 相似文献
Time-lapse distortion patterns with characteristic time-shift versus offset signatures are observed. The positions and vertical extents of the distortion zones are determined from ray path considerations and modelling. The distortion zones correlate with buried faults, indicating that a (time-lapse) distortion zone might be produced by a localized slip in a fault zone. We present an extended method which allows for vertical (in addition to lateral) variations in the relative thickness and velocity changes. This method can be viewed as a simplified version of time-lapse tomography, but involving fewer unknown parameters, giving more stability to the estimated changes in thickness and velocity. Using this technique, we are able to estimate α for positions with localized time-lapse distortions. 相似文献