Safety assessment of infrastructures using a new Bayesian Monte Carlo method     

《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2013,7(3-4):195-206

A recently developed Bayesian Monte Carlo (BMC) method and its application to safety assessment of structures are described in this paper. We use a one-dimensional BMC method that was proposed in 2009 by Rajabalinejad in order to develop a weighted logical dependence between successive Monte Carlo simulations. Our main objective in this research is to show that the extended BMC can dramatically improve simulation efficiency by using prior information from modelling and outcomes of preceding simulations. We provide theory and numerical algorithms for an extended BMC method for multi-dimensional problems, integrate it with a probabilistic finite element model and apply these coupled models to assessment of reliability of a flood defence for the 17th Street Flood Wall system in New Orleans. This is the first successful demonstration of the BMC method to a complex system. We provide a comparison of the numerical efficiency for the BMC, Monte Carlo (MC) and Dynamic Bounds methods that are used in reliability assessment of complex infrastructures.  相似文献   

Effect of shape on holding capacity of plate anchors buried in soft soil     

《Geomechanics and Geoengineering》2013,8(2):145-154

Plate anchor is one of the most common varieties of anchors used in the construction and maintenance work of various on-land and offshore structures. An accurate estimation of the uplift capacity of anchor foundations is necessary for an economical design as well as for the safety and stability of structures. This paper outlines the effect of shape of anchor plates on their breakout capacity, through a series of model tests. Both shallow and deep anchor behaviours were investigated under conditions developing suction force and without suction force. The results of these tests are presented in terms of load-displacement behaviour, variation of breakout factors (with and without suction force) with depth of embedment, the critical embedment depth of anchors and variation of suction force with embedment ratio. Further, the variations of breakout factor ratio with aspect ratio and embedment ratio are reported. Based on the experimental results and the model test results of other investigators an empirical relationship has been suggested to determine the shape factor and holding capacity of plate anchors buried in saturated cohesive soils.  相似文献   

门源6.4级、共和7.0级地震前后波速比变化特征   总被引：2，自引：0，他引：2  

都昌庭  徐兰芬  冀金梅 《高原地震》1997,(2)

通过来用门源台、湟源台所记录的地震资料，对1986年门源6．4级地震、1990年共和7．0级地震前后进行波速比-时空分析，发现两次地震前后其时间分布形态为持续低值-恢复-发震的现象，空间分布为圆形、椭圆形的异常区，震后异常区消失。  相似文献   

新疆和周边地区地壳厚度和Vp/Vs比值变化的接收函数约束          下载免费PDF全文

刘文学  刘贵忠  周刚  李欣  张慧民  徐恒垒 《地球物理学报》2011,54(8):2034-2041

我们用修订后的接收函数H-K叠加算法估计了新疆和周边地区90个地震台站下的地壳厚度和波速比Vp/Vs.该地区平均地壳厚度约为52 km,变化范围约为33～79 km.最厚地壳位于西昆仑山的TAG台站,最薄地壳在塔拉斯-费尔干那断层附近的NRN台站.对每个台站的点地壳厚度估计结果进行了线性各向同性变差模型的标准克里金空间...  相似文献   

苍山地震与新沂台前兆异常   总被引：1，自引：0，他引：1  

李飞  杨冯威 《东北地震研究》2002,18(2):37-41

根据新沂台前兆资料，运用加卸载响应比、差分法对地磁场Z分量进行分析；运用滑动平均对短水准资料进行分析；运用速率法对视电阻率进行分析；结果表明：在苍山地震前，新沂台前兆资料具有良好的中、短期异常，并有进入临震的异常标志。  相似文献   

Crustal transect from the North Atlantic Knipovich Ridge to the Svalbard Margin west of Hornsund   总被引：1，自引：0，他引：1  

Frode Ljones  Asako Kuwano  Rolf Mjelde  Asbjrn Breivik  Hideki Shimamura  Yoshio Murai  Yuichi Nishimura 《Tectonophysics》2004,378(1-2):17-41

The crustal structure along a 312 km transect, stretching from the axial mountains of the North Atlantic Knipovich Ridge to the continental shelf of Svalbard, has been obtained using seismic reflection data and wide angle OBS data. The resulting seismic V_p and V_s models are further constrained by a 2-D-gravity model. The principal objective of this study is to describe and resolve the physical and compositional properties of the crust in order to understand the processes and creation of oceanic crust in this extremely slow-spreading counterpart of the North Atlantic Ridge Systems. V_p is estimated to be 3.50–6.05 km/s for the upper oceanic crust (oceanic layer 2), with a marked increase away from the ridge. The measured V_p of 6.55–6.95 km/s for oceanic layer 3A and 7.10–7.25 km/s for layer 3B, both with a V_p/V_s ratio of 1.81, except for slightly higher values at the ridge axis, does not allow a clear distinction between gabbro and mantle-derived peridotite (10–40% serpentized). The thickness of the oceanic crust varies a lot along the transect from the minimum of 5.6 km to a maximum of 8.1 km. The mean thickness of 6.7 km for the oceanic crust is well above the average thickness for slow-spreading ridges (<10 mm/year half-spreading rate). The areas of increased thickness could be explained by large magma production-rates found in the zones of axial highs at the ridge axis, which also have generated the off-axial highs adjacent the ridge. We suggest that these axial and off-axial highs along the ridge control the lithological composition of the oceanic crust. This approach suggests normal gabbroic oceanic crust to be found in the areas bound by the active magma segments (the axial and off-axial highs) and mantle-derived peridotite outside these zone.  相似文献   

海相软土压缩特性的试验研究   总被引：1，自引：0，他引：1  

陈波  孙德安  吕海波 《岩土力学》2013,34(2):381-388

对不同取样方式得到的上海、江苏地区海相软黏土的原状样和重塑样进行了单向压缩和等向压缩试验,分别得到各自的压缩曲线、压缩指数 和回弹指数 。通过比较原状样、重塑样的归一化压缩曲线的差异,确认了结构性对软黏土压缩特性的影响。把屈服应力后的压缩曲线外延至10 kPa时的孔隙比定义为参考孔隙比 ,用于简单量化土的组构。根据多次单向压缩试验结果得到的压缩指数 ,建立了原状样和重塑样的压缩指数 与孔隙比 或参考孔隙比 的相关方程,并通过单向、等向压缩指数的比较,认为此方程也适用于等向压缩试验结果。根据原状、重塑样压缩指数 与参考孔隙比 具有基本相同关系的结论,对原状样的结构屈服特性进行了探讨,认为原状样在压力大于结构屈服应力后,胶结已基本破坏,原状样和重塑样压缩特性差异主要是由组构的差异引起的。该研究成果,尤其是压缩指数 与参考孔隙比 的相关方程,可为工程提供重要的参考。  相似文献   

脉冲压缩方法检测岩石弹性波速度     

李长征  张碧星  师芳芳 《岩土力学》2013,34(6):1815-1821

针对岩石弹性波速度检测信噪比低、回波信号初至时间不易判读,以及较长岩石（或混凝土）超声检测难以穿透问题,提出用脉冲压缩方法检测弹性波速度。该方法与超声脉冲法检测的不同之处是在发射端采用编码信号激励,在接收端进行匹配滤波,得到高信噪比的压缩信号。介绍线性调频信号的宽时宽带特性,分析了脉冲压缩的基本原理和数字实现过程。试验研究了换能器带宽对激发信号的影响。用常规的单脉冲法和脉冲压缩方法检测了多个岩样的弹性波速度,试验结果表明,两种检测结果差异较小。给出了脉冲压缩方法用于岩石弹性波速度检测的具体步骤和计算过程。综合分析,脉冲压缩方法检测岩石弹性波速度是可行的,能够用于岩土工程的质量评价。  相似文献   

Improving Coalbed Methane Recovery Ratio by Injecting Hot Carbon Bioxide     

CAI Jihu  YUAN Ye  GU Sui  LIU Hao 《《地质学报》英文版》2013,87(Z1):934-935

  相似文献   

烷基酚的油水分配系数影响因素研究     

孙砚泽  彭晓波  文志刚  何文祥  严刚  刘栩  钟鸣  田伟超 《地质力学学报》2022,28(2):217-225

烷基酚是一类由酚类化合物烷基化后产生的化合物,与其他非烃化合物相比,更易溶于水.文章通过不同温度(25℃、45℃和65℃)、 不同盐水浓度(4000 mg/L、6000 mg/L和8000 mg/L)和不同原油类型(X37、X45和X61)的三组油水分配实验,研究了烷基酚在油水两相间的分配特征,确定了烷基酚分配系数的变...  相似文献