三峡库区云阳塞坝"平台式"斜坡变形机理分析     

王建锋  苏爱军  尹先忠  刘大显  王怀球  吴梦喜 《水文地质工程地质》2003,30(4):1-6

以三峡库区云阳塞坝滑坡为例,分析了层状砂泥岩区缓坡平台上崩滑堆积物中因开挖引起变形的机理。研究表明,崩滑堆积物呈蜂窝状分布的富水含水层,因远距离开挖失水而导致的不均匀变形,是地面出现拉裂的主要原因;平台中的公路开挖所诱发的边坡回弹变形仅限于局部范围。这两类变形的发生在时间上或相应的施工期间可能表现为表观的“同步”现象,但不均匀变形随着含水层排水的完成而结束,而开挖所诱发的回弹变形,则可以随着外界条件的变化而不断发展。直至发生滑坡。在空间上,两类变形具有不同的特征,其中,不均匀固结变形的发生以不规则的孤立含水层为中心向外发展,而回弹变形则局限于临空面附近,远离临空面时变形量和变形速率迅速减小。在富含地下水的松散堆积物中进行工程施工时,区分两类变形机理和效应,对于减少滑坡误判,正确进行工程设计,减少工程造价具有重要意义。  相似文献   

南黄海地区中强地震的发震背景     

史雯  李炜  卢桦楠 《地震地磁观测与研究》2003,24(6):5-7

依据《地震分析预报方法指南》,利用MAPSIS软件,对南黄海地区发生中强地震前的地震活动及相关地震学参数进行了分析研究,概述了该地区中强震前的发震背景。  相似文献   

An experimental study on semi-brittle and plastic rheology of Panzhihua gabbro   总被引：10，自引：0，他引：10  

何昌荣  周永胜  桑祖南 《中国科学D辑(英文版)》2003,46(7):730-742

Rheological properties of the crust and upper mantle are essential data that are needed in modelling the mechanical behaviour of the shallow part of the earth. The importance of such data has been seen in discussions about the strength profile of continen…  相似文献   

附加系统参数的平差模型研究     

刘青利  隋立芬 《测绘学院学报》2004,21(1):5-7,10

考虑到系统误差源的复杂性，文中提出了一种附加系统参数的混合平差模型，导出了平差公式和假设检验统计量。附加系统参数的混合平差模型中，同时含有非随机系统参数和具有验前统计性质的随机系统参数。该平差模型是对附加系统参数的平差模型的扩展。  相似文献   

祁连山中东段地区三维速度结构研究   总被引：16，自引：1，他引：16       下载免费PDF全文

张元生  周民都  荣代潞  张立光  许中秋 《地震学报》2004,26(3):247-255

应用中——法数字化地震台网自1996年以来所记录到的微震S-P资料，对祁连山中东段地区三维速度结构与震源参数进行了联合反演，获得了该区的三维速度成像．速度结果反映出深部构造的一些重要信息，为进一步研究该区的活动构造及地震参数计算，提供了科学依据．   相似文献   

岩石粘弹性非定常蠕变方程的参数辨识   总被引：10，自引：1，他引：10  

丁志坤  吕爱钟 《岩土力学》2004,25(Z1):37-40

近年来,由于力学试验手段和技术的迅速发展,岩石的流变试验的研究也取得了极大的进展。在此基础上,不少学者开始着手探索基于试验结果分析来建立非线性的粘弹性本构模型。作者在页岩蠕变试验数据的基础上,分析了岩石粘弹性变形随应力水平不同和时间发展的变化规律。从元件型本构方程出发验证引入非定常参数的必要性。建立了一维情况下非定常粘弹性模型的蠕变方程,通过理论计算结果与试验结果的对比,发现非定常粘弹性模型比定常粘弹性模型更为准确的反映了岩石的粘弹性变形性能。  相似文献   

基于遗传算法的煤层注水渗透特征参数反演     

李宗翔  郭嗣琮  倪景峰 《中国地质灾害与防治学报》2004,15(4):60-63

煤层注水是防治矿井冲击地压灾害发生的最有效的方法。确定煤层渗透特征参数，是合理确定注水工艺参数、有效控制防灾效果的关键，有很强的现实意义。遗传算法是全局收敛的方法，用该算法对煤体导水、贮水等渗透特征参数反演，方法稳定可靠。以观测水分增值与计算结果的相对偏差作为最优搜索目标函数，建立GA反演适应度函数及迭代收敛准则；GA操作采用无条件保护最优个体、种群个体无死亡及每个体只有1次参与交换机会等规则。提出通过对已知参数正向问题结果(水分增值)的反演计算，验证遗传算法精度。算例结果表明，繁衍迭代至第41代时，反演参数结果与理论参数几乎完全拟合。达到最优解，精度符合工程要求。  相似文献   

Including prior information in the estimation of effective soil parameters in unsaturated zone modelling   总被引：2，自引：0，他引：2  

J Mertens  H Madsen  D Jacques 《Journal of Hydrology》2004,294(4):251-269

In this paper we propose a methodology to include prior information in the estimation of effective soil parameters for modelling the soil moisture content in the unsaturated zone. Laboratory measurements on undisturbed soil cores were used to estimate the moisture retention curve and hydraulic conductivity curve parameters. The soil moisture content was measured at 25 locations along three transects and at three different depths (surface, 30 and 60 cm) on an 80×20 m hillslope for the year 2001. Soil cores were collected in 84 locations situated in three profile pits along the hillslope. For the estimation of the effective soil hydraulic parameters the joint probability distribution of measured parameter values was used as prior information. A two-horizon single column 1D MIKE SHE model based on Richards' equation was set-up for nine soil moisture measurement locations along the middle transect of the hillslope. The goal of the model is to simulate the soil moisture profile at each location. The shuffled complex evolution (SCE) algorithm has been applied to estimate effective model parameters using either wide parameter ranges, referred to as the ‘no-prior’ case, or the joint probability distribution of measured parameter values as prior information (‘prior’ case). When the prior information is incorporated in the SCE optimisation the goodness-of-fit of the model predictions is only slightly worse compared to when no-prior information is incorporated. However, the effective parameter estimates are more realistic when the prior information is incorporated. For both the no-prior and prior case the generalised likelihood uncertainty estimation procedure (GLUE) was subsequently used to estimate the uncertainty bounds (UB) on the model predictions. When incorporating the prior information more parameter sets were accepted for the estimation of the predictive uncertainty and the parameter values were more realistic. Moreover, UB better enclosed the observations. Thus, incorporating prior information in GLUE reduces the amount of model evaluations needed to obtain sufficient behavioural parameter sets. The results indicate the importance of prior information in the SCE and GLUE parameter estimation strategies.  相似文献   

Identification of base‐excited structures using output‐only parameter estimation     

Brad A. Pridham  John C. Wilson 《地震工程与结构动力学》2004,33(1):133-155

This paper presents a new identification technique for the extraction of modal parameters of structural systems subjected to base excitation. The technique uses output‐only measurements of the structural response. A combined subspace‐maximum likelihood algorithm is developed and applied to a three‐degree‐of‐freedom simulation model. Five ensembles of synthetically generated input signals, representing varying input characteristics, are employed in Monte Carlo simulations to illustrate the applicability of the method. The technique is able to circumvent some of the difficulties arising from short data sets by employing the Expectation Maximization (EM) algorithm to refine the subspace state estimates. This approach is motivated by successful application by previous authors on speech signals. Results indicate that, for certain system characteristics, more accurate pole estimates can be identified using the combined subspace‐EM formulation. In general, the damping ratios of the system are difficult to identify accurately due to limitations on data set length. The applicability of the technique to structural vibration signals is illustrated through the identification of seismic response data from the Vincent Thomas Bridge. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

地震信息反馈系统的研制和应用     

何寿清  叶春明  谢剑波  郭德顺  王国望 《地震地磁观测与研究》2004,(Z1)

介绍了地震信息反馈系统的原理和功能,给出了系统的结构框图,对发送终端和接收终端的功能做了具体描述。在应用上也做了具体阐述,该系统能有效、快速地传送地震三要素信息。  相似文献