Gibson大变形固结理论的一种连续介质力学表述     

袁大军  丁洲祥  朱合华  蒋明镜 《岩土力学》2009,30(7):1904-1908

为了克服Gibson大变形固结理论的一维局限性,提出了一个新的连续介质力学模型,其中,采用第2类Piola- Kirchhoff应力和Green应变分别替代Lagrange应力和孔隙比。该模型可以考虑土体压缩性和渗透性的非线性变化以及几何非线性,并具有易于推广到多维模型的优势。结合试验资料,探讨了新模型的固结系数和对流系数的变化规律,结果表明,对流系数随着应变增加而减小,反映了大变形固结过程中土体自重效应在不断减弱。  相似文献   

新峰一矿构造控水作用与治理措施探讨     

王书华  ;王松森  ;张孔敏  ;王彩勤 《中国煤炭地质》2009,(4):38-43

新峰一矿突水频繁,矿井安全受水害威胁严重,防治工程量大、难度高。通过对矿井构造应力展布规律、矿井边界及矿井内断层导水性等水文地质因素的分析,确定了该矿井突水类型。指出石炭系灰岩裂隙水和寒武系灰岩裂隙水是矿井的主要充水含水层,断裂构造是主要导水通道。地质构造对突水的控制在该矿主要体现在对突水点分布、富水带的划分以及隔水层阻水能力等方面。在对影响该区地质构造机理进行综合分析的基础上,根据矿区构造控水的特点,提出了采取物探和钻探相结合、进行放水试验、帷幕注浆和排供结合的治理措施。  相似文献   

G214盐井-芒康段地质灾害调查中遥感技术的应用     

张玉明  汤喜梅 《中国地质灾害与防治学报》2009,20(1):94-98

滇藏公路是由西南进入西藏地区的唯一通道。历年来沿线地质灾害不断,损失严重。通过遥感技术的应用,选取新时相的卫星遥感影像,对公路沿线的地质灾害和构造体系进行全面、宏观的调研。可以快速系统地查明滇藏公路地质灾害的分布、类型和形成的地质背景。客观地反映沿线地质灾害的形成规律,为下一步的公路选线和设计、维护和治理提供科学依据。  相似文献   

Time–space fractional governing equations of one‐dimensional unsteady open channel flow process: Numerical solution and exploration          下载免费PDF全文

Ali Ercan  M. Levent Kavvas 《水文研究》2017,31(16):2961-2971

Although fractional integration and differentiation have found many applications in various fields of science, such as physics, finance, bioengineering, continuum mechanics, and hydrology, their engineering applications, especially in the field of fluid flow processes, are rather limited. In this study, a finite difference numerical approach is proposed to solve the time–space fractional governing equations of 1‐dimensional unsteady/non‐uniform open channel flow process. By numerical simulations, results of the proposed fractional governing equations of the open channel flow process were compared with those of the standard Saint‐Venant equations. Numerical simulations showed that flow discharge and water depth can exhibit heavier tails in downstream locations as space and time fractional derivative powers decrease from 1. The fractional governing equations under consideration are generalizations of the well‐known Saint‐Venant equations, which are written in the integer differentiation framework. The new governing equations in the fractional‐order differentiation framework have the capability of modelling nonlocal flow processes both in time and in space by taking the global correlations into consideration. Furthermore, the generalized flow process may possibly shed light on understanding the theory of the anomalous transport processes and observed heavy‐tailed distributions of particle displacements in transport processes.  相似文献   

福建福清核电厂厂址地质环境条件浅析     

林榕萍 《福建地质》2008,27(3):308-315

通过对福清核电厂厂区附近地质构造特征以及岩土工程勘察和水文地质调查进行综合评价,并对厂区内可能出现不良地质体的成因进行了分析,提出需要治理改造的建议。  相似文献   

核废料储库周边介质热力耦合数值分析   总被引：4，自引：2，他引：2  

白冰 《岩土力学》2004,25(12):1989-1993

以热力学和热弹性理论为基础,分析热-力相互耦合作用及其对热特性参数和力特性参数的影响。建立了非等温条件下的耦合作用控制方程,给出了相应的空间离散和时间离散形式。利用有限元法对一核废料储库的平面问题进行了计算,讨论了储库周围粘性土介质内温度场、应力场等的动态发展变化规律,并分析了耦合效应对计算结果的影响。研究表明,随时间的增长,热能由储库边壁不断向远处传导和扩散,而在空间上又处于不断变化的非等温状态,这一动态变化过程必然会诱致周围土介质内应力的产生和发展,并随温度的变化而不断变化。  相似文献   

A singular perturbation method for parametric investigation on J-lay installation of deepwater pipelines     

王琴  段梦兰  李海明  张庆元 《中国海洋工程》2013,27(6):751-766

The maximum bending moment or curvature in the neighborhood of the touch down point （TDP） and the maximum tension at the top are two key parameters to be controlled during deepwater J-lay installation in order to ensure the safety of the pipe-laying operation and the normal operation of the pipelines. In this paper, the non-linear governing differential equation for getting the two parameters during J-lay installation is proposed and solved by use of singular perturbation technique, from which the asymptotic expression of stiffened catenary is obtained and the theoretical expression of its static geometric configuration as well as axial tension and bending moment is derived. Finite element results are applied to verify this method. Parametric investigation is conducted to analyze the influences of the seabed slope, unit weight, flexural stiffness, water depth, and the pipe-laying tower angle on the maximum tension and moment of pipeline by this method, and the results show how to control the installation process by changing individual parameters.  相似文献   

南海夏季风强度与我国汛期降水的关系   总被引：38，自引：24，他引：38       下载免费PDF全文

吴尚森  梁建茵  李春晖 《热带气象学报》2003,19(Z1):25-36

对4种南海夏季风强度指数(1951～1998年)进行了对比分析,发现尽管它们在某些年份有差异,但在年际变化总体趋势上仍表现一致,并且由它们所确定的季风强弱年也基本相同.统计分析了南海夏季风强度与我国汛期降水的关系,结果表明,南海夏季风强(弱)年,我国夏季雨带型呈Ⅰ(Ⅲ)类分布,长江中下游地区夏季(6～7月)少雨干旱(多雨洪涝),广东省后汛期降水以偏涝(正常和偏旱)为主.南海夏季风强度指数与夏季长江中下游区降水和淮河区降水有显著的反相关,与江南区降水和华南后汛期降水有显著的正相关.我国夏季出现的严重洪涝(如1998年长江流域特大洪涝和1994年华南特大暴雨)与南海夏季风的强度异常有关.此外,分析还表明,南海夏季风活动强弱造成的北半球东亚500 hPa位势高度场的经向波列型遥相关是影响中国夏季降水的一个重要机制.  相似文献   

DISSIPATION EFFECT ON THE FLOW OVER MOUNTAINS_*     

Wu Rongsheng  Fang Juan 《Acta Meteorologica Sinica》1997,11(2):196-203

In the paper,the turbulent dissipation is considered in the model for studying the flow over mountains.The governing equation is a first order ordinary differential equation derived from an algebraic equation without dissipation case.The solution is sensitive to the upstream condition of dissipation.The dissipation not only reduces the strength of discontinuity but also changes the properties of the governing equation.In the paper,the qualitative characteristic features of the governing equation are discussed.The numerical results with super and sub-critical cases are also discussed in detail.The results show that the turbulent dissipation is an important factor and is not negligible.  相似文献   

工作面顶板动态离层水治理研究     

李忠凯  胡杰 《中国煤田地质》2007,19(2):35-37

2005年5月21日淮北矿业集团海孜煤矿745工作面发生了瞬时水量达3887m^3/h的特大溃水事故.经分析发现,此次溃水事故的水源来自7煤层顶板砂岩离层积水,是在复杂水文工程地质条件下,采煤工作面顶板产生的一种动态突水水源.针对离层突水的动力特点,在工作面回采影响以外的下山方向布置钻孔,并采取在工作面采前、采中和采后持续放水的措施,有效地阻止了离层水源的产生,保证了工作面安全生产.  相似文献