抛掷型岩爆震源体能量动态释放机制与几何尺度特征

为了进一步理解岩爆的机制并解释岩爆发生的过程,通过对抛掷型岩爆能量来源、去处及大小的分析,提出了抛掷型岩爆的震源两体模型。抛掷型岩爆本质上是释能体-岩爆体相互作用下岩石裂纹动态扩展和能量快速释放的过程。从岩爆体张拉断裂机制出发,采用脆性内聚裂纹阵列扩展动力学模型分析了裂纹间距与应变率对岩爆体能量释放速率的影响。据此得出释能体对岩爆体的作用可归结为应变率效应,释能体能量释放速率越大,对岩爆体的动态加载速率就越大,使得岩爆体能量释放速率加快。岩爆体破裂能量释放速率越大,作用于释能体的动态卸载速率就越大,又使得释能体的能量释放速率增大,两体相互作用形成的动态加、卸载效应构成了岩爆能量释放的正反馈机制。基于上述理论推导得出岩爆震源体的几何尺度是岩爆体的几倍到几十倍,理论结果与现场实际监测分析基本吻合。     

混凝土开裂对地基板弯矩的影响

当前地基板的配筋设计均按弹性体计算得到的弯矩进行，这在理论上是不合理的，因为地基板是高次超静定问题，地基板开裂后其弯矩会有较大的改变。笔者通过合理模拟地基板裂缝开展过程及土．结构的相互作用，采用非线性有限单元法对地基板进行了分析，着重讨论了不同计算方法及裂缝对地基板弯矩的影响。计算结果表明，按平面问题计算得到的弯矩比按空间问题大40％左右，地基板开裂后弯矩减小，且裂缝越多，弯矩减小越多。     

基于Visual Basic及Access的工程资料档案管理系统开发

在社会日趋发展和信息技术取得巨大进步的今天，许多勘查设计单位原有的工程资料管理方法已不能完全满足社会各方面工程实践的要求，使用先进的工程资料管理系统是必不可少的。因此，工程资料档案管理系统是一卜具有重要理论研究意义及广阔应用前景的研究课题。文章结合鹧鸪山隧道这一重大工程，利用visual Basic和Access开发了一个适用于广大工程建设资料管理的软件。在系统开发过程中，解决了以下问题，即利用WinRAR软件实现文，牛的压缩及解压缩，利用SQL语言实现文件多种查询方法。通过调用文件存放地址实现文件的打开功能。工程资料卡当案管理系统的使用将解决工程实际中存放、保管资料的各种问题，消除了传统资料保存方式的弊端。工程资料档案管理系统具有使用方便、查询快捷等优点，具有实用价值和推广价值。     

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

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.     

大规模多岛屿海域潮流场的数值模拟

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。     

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

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.     

地震作用下双层土裂缝边坡稳定性分析

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。