含环向表面裂纹管道功率流特性与裂纹识别     

李天匀  朱翔  赵耀  严谨 《海洋工程》2007,25(1):57-63

研究在外力激励下含有环向表面裂纹损伤的壳式管道的波传播与功率流特性,并给出裂纹识别方法。管道的振动用Flügge方程来描述,通过将裂纹模拟为分布的线性弹簧,运用断裂力学理论,得到裂纹区域的局部柔度矩阵,从而建立外力作用处以及裂纹两侧区域的位移和内力的连续性条件对裂纹管道的功率流进行求解。讨论功率流特性与裂纹位置和管道特性等参数的关系,最后给出了裂纹识别的方法。  相似文献   

论赤平极射投影在山口岩水利工程中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

陈炳贵  方宏伟 《地球物理学进展》2008,23(2):631-635

本论文首先简单介绍了水利工程中分析岩质边坡稳定性常用的一种图解法——赤平极射投影法,然后介绍了这种方法在山口岩水利工程稳定性分析中的具体应用,因其在该水利工程的坝基和岩质边坡稳定性分析中发挥了一定的作用,满足了工程实践的要求,故希望对其它水利工程坝基抗滑和岩质边坡的稳定性分析具有指导意义.  相似文献   

港仔地裂缝——雷州半岛西部一条纵贯晚全新世砂堤地裂缝的发现          下载免费PDF全文

徐起浩 《第四纪研究》2008,28(4):712-720

港仔地裂缝发生于新生代以来强烈活动的琼雷凹陷北部雷州半岛的西海岸,沿构造带展布,形成于凸起和凹陷交界地区。地裂缝局部纵贯沿海岸展布的晚全新世砂堤,切过中更新世火山岩及其风化土和全新世海成阶地。根据其展布区的构造、地形地貌和形成特征,并与近几十年雷州半岛大量发生的地裂缝比较,认为港仔地裂缝可能属构造蠕变地裂缝。该地裂缝揭示了被纵贯砂堤的沉积学特征和形成于巨砾海滩和高能海浪下的古环境。砂堤上部约海拔5m砂堤岩取样¹⁴C测年为1360±60aB.P.,结合雷州半岛西海岸、西南海岸其他抬升特征,推测该地裂缝是在晚全新世该地海岸抬升或抬升后形成的。  相似文献   

Study on collapse settlement and cracks of core wall rockfill dams under wetting deformation     

Xiongxiong Zhou  Jichun He  Shichun Chi  Jinwei Wang 《国际地质力学数值与分析法杂志》2023,47(1):106-128

The safety and stability of core wall rockfill dams during impoundment are threatened by the wetting deformation of up-stream shell materials. The serious wetting deformation not only aggravates the collapse settlement of upstream rockfill but also intensifies differential settlement of the dam crest during impoundment, and then causes cracks on the dam crest. On the basis of the proposed wetting deformation model and its simulation method of wetting deformation, this paper simulated the impoundment process of Guanyinyan core wall rockfill dam and studied the deformation characteristic of the dam during impoundment. In addition, the smeared cracking model was used to simulate the crack propagation on the dam crest, and the crack develop and spread mechanism was analysed. The results show that the simulated deformation can fit the in-situ data well, and the simulated crack propagation is in good agreement with the actual situation. Once watered, the upstream rockfill and core wall have significant settlement, and the whole dam crest has obvious horizontal displacement towards the upstream. It is on the same order of magnitude that the increment of horizontal displacement and settlement at the top of the dam during impoundment. In the process of impoundment, the upper part of the dam tends to deform towards the reservoir area, which will lead to tensile cracks appearing in the rockfill areas on both upstream and downstream sides of the core wall of the dam crest, and the propagation direction of the cracks is basically parallel to the adjacent core wall surface. With the water level rising, the cracks on the downstream side of the dam crest mainly extend vertically, and the cracks on the upstream side of the dam crest not only extend vertically, but also extend horizontally.  相似文献   

大规模多岛屿海域潮流场的数值模拟   总被引：6，自引：0，他引：6  

周发毅  郭勇  虞和莹 《海洋工程》1995,(4)

本文提出了一种系统地分析大规模多岛屿海域潮流场的数值模拟方法,以及只有有限代表点位的计算区域内的潮汐和潮流资料的分析方法。建立了适用于复杂的多岛屿海域上平面二维潮波数值计算模型的选择及网格自动剖分方法。通过对长海县长山群岛海域潮流场的模拟,验证了此方法在计算规模大而又要求局部分辨率高的潮流场时,该方法效率高,经济合理,灵活方便。  相似文献   

The Continuum Voronoi Block Model for simulation of fracture process in hard rocks     

Erick Rgenes  Mrcio Muniz de Farias  Leandro Lima Rasmussen 《国际地质力学数值与分析法杂志》2022,46(1):89-112

In this paper, a numerical model is presented to represent the fracture process in hard rocks based on a pseudo-discontinuum method called the Continuum Voronoi Block Model (CVBM). To validate this tool, numerical models for one Brazilian test, one unconfined compression test, and multiple triaxial compression tests with different confining stress were calibrated to match laboratory test results for Creighton granite. The model proved robust and matched the following macro-properties: crack initiation (CI) stress, (CD) stress, peak strength, tensile strength, Young's Modulus, and Poisson's ratio. The calibrated model served as a basis for a sensitivity study to analyze how micro-properties influence the rock's macroscopic responses. From the sensitivity study, a calibration methodology was proposed, which shall facilitate the use of the CVBM in future works.  相似文献   

地震作用下双层土裂缝边坡稳定性分析          下载免费PDF全文

梁承龙  刘芳 《地震工程学报》2022,44(5):1050-1058

裂缝常存在于边坡表面，地震作用会大幅降低裂缝边坡稳定性。针对双层土裂缝边坡稳定性问题，定义上下土层分界处高度与边坡高度之比为深度系数以描述双层土的分布，基于极限分析上限定理，构建“点到点”离散运动学机构，并在此机构中引入一条垂直张拉裂缝，结合拟静力法和强度折减法建立能量平衡方程求解裂缝边坡临界高度和安全系数上限解。计算结果与传统上限法进行对比，验证离散运动学机构的有效性及其解的优越性，同时探究土体非均质性及深度系数对裂缝边坡稳定性以及裂缝深度和位置的影响规律。结果表明，地震作用会降低边坡稳定性；随着地震力增大，边坡临界滑动面逐渐加深，裂缝深度略微增大，裂缝位置逐渐远离坡面；对于具体的双层土边坡会存在一个特定的深度系数使边坡安全系数达到最值，同时裂缝会穿越至下层土且深度发生突增。  相似文献