Population balance in confined comminution using a physically based probabilistic approach for polydisperse granular materials

A novel, simplified approach is presented in order to compute variations of grading in granular assemblies during confined comminution under quasi‐static compression. The method is based on a population balance equation and requires a breakage probability, considered here as a probabilistic phenomenon that takes into account the particle strength and the loading condition of individual grains. Under basic assumptions, a simple breakage probability can be defined in order to get a valuable result for engineering applications and powder technology. The size effect in the strength of individual particles is introduced according to Weibull's theory. The particle loading and the cushioning effect in the granular packing are accounted for by considering the orientations of the contact forces obtained from 3D discrete element method simulations of highly polydisperse materials. The method proposed could have a value for engineering purposes in powder technology and geomechanics and gives a general framework for further research developments based on population balance. Copyright © 2016 John Wiley & Sons, Ltd.     

Evaluation of the seismic response of masonry buildings based on energy functions

This work is based on energies evaluated from the responses of 12 stone and brick masonry systems subjected to 58 shaking table tests. The evolution of input energy during a damaging base excitation is correlated to the change of the damage patterns of the considered buildings. The comparison among energies dissipated and absorbed by the buildings during the various shocks gives some hints on strengthening strategies. It is found that damage to spandrel beams produces a more significant energy absorption than other types of damage. Copyright © 2001 John Wiley & Sons, Ltd.     

山西朔州市北邢家河饮用天然矿泉水

朔州市北邢家河村ＳＢ－２井，为第四系松散层孔隙承压水，井深７ｌｍ，水位埋深１０．０５ｍ。动水位埋深１７．８ｍ，涌水量５８．８５ｍ￣３／ｈ。经权威部门理化检测，省级评审确认该井水为低矿化度、锶、重碳酸钙·镁型饮用天然矿泉水，具良好的开发利用条件。     

大口径井开采中埋深高承压岩溶水探讨

本文以工程实例，论述了中埋深高承压岩溶水的勘探及大口径井开发的技术问题，与同行共同切磋。     

钢筋混凝土框架结构全过程pushover分析

以往采用杆系模型对钢筋混凝土结构进行pushover分析时，杆端塑性铰所采用的力一变形关系模型中特征参数的计算是基于杆件的原始尺寸，且对变形的极限值(如极限曲率)没有加以限制，这种本构模型并不能完整地体现构件的受力全过程。本文首先采用数值计算方法分析了钢筋混凝土压弯构件保护层混凝土剥落后强度的变化以及箍筋约束作用对其强度和延性的影响。在此基础上，以一个预应力混凝土框架结构为例进行了全过程pushover分析。算例分析结果表明，这种分析方法能够更合理地反映结构从加载到破坏的整个受力过程。     

砖混结构墙体冲击承载性能的实验研究

以云南东川蒋家沟实际观测资料为基础，研究砖混结构建筑墙体在受到泥石流体中携带的大石块冲击力作用下的受力形式及破坏形态；在此基础上，进行了砖混建筑结构墙体模型试件的破坏性实验，现场观测试件在平面内和平面外两种冲击力作用方式下的破坏形态和历程，采集其动态位移、振幅及主振频率数据，经计算分析得出结构动态响应模式。     

Experimental and analytical studies on earthquake resisting behaviour of confined concrete block masonry structures

To improve the seismic performance of masonry structures, confined masonry that improves the seismic resistance of masonry structures by the confining effect of surrounding bond beams and tie columns is constructed. This study investigated the earthquake resisting behaviour of confined masonry structures that are being studied and constructed in China. The structural system consists of unreinforced block masonry walls with surrounding reinforced concrete bond beams and tie columns. The characteristics of the structure include: (1) damage to blocks is reduced and brittle failure is avoided by the comparatively lower strength of the joint mortar than that of the blocks, (2) the masonry walls and surrounding reinforced concrete bond beams and tie columns are securely jointed by the shear keys of the tie columns. In this study, wall specimens made of concrete blocks were tested under a cyclic lateral load and simulated by a rigid body spring model that models non‐linear behaviour by rigid bodies and boundary springs. The results of studies outline the resisting mechanism, indicating that a rigid body spring model is considered appropriate for analysing this type of structure. Copyright © 2006 John Wiley & Sons, Ltd.     

山西省汾河灌区地下水系统分析

本文运用有关地下水系统理论，对山西省汾河灌区地下水资源作系统分析。灌区水资源系统由地表水系统与地下水系统构成。地下水系统具有双层含水结构；浅层潜水——承压水系统和中层承压水系统。由于含水系统本身特点及人工开采影响，浅层水对中层地下水垂直越流补给。地下水属松散孔隙水。地下水运动以全向为主，水平运动为辅。     

用碳纤维布改善混凝土小型空心砌块墙体抗震性能的试验研究

通过4片碳纤维布加固混凝土小型空心砌块墙体在周期反复荷载作用下受力性能的试验，研究了用粘贴碳纤维布来增强混凝土小型空心砌块墙体抗震能力这种加固方法的有效性。本文研究了碳纤维布加固混凝土小型空心砌块墙体的受力特性，分析了碳纤维布不同用量对混凝土小型空心砌块墙体抗震加固效果的影响。在此基础上，本文提出了碳纤维布加固混凝土小型空心砌块墙体抗剪承载力的简化计算方法，可供实际抗震加固工程设计参考。     

基于性态的砌块砌体结构极限性态目标位移确定方法的研究

对砌块砌体结构进行Push—over分析，其结果准确与否和结构的极限性态目标位移的可靠确定关系很大。本文基于大量的配筋砌块砌体墙片试验结果，对直接基于位移的抗震设计法进行改进，使之能够用于砌块砌体结构的极限性态目标位移的确定。用改进的方法求解一座1／4比例的10层砌块砌体模型结构的极限性态目标位移，并与该模型结构的振动台试验结果进行比较。结果说明本文提出的改进方法是可以应用于求解砌块砌体结构的极限性态目标位移的。