某储罐基础在爆炸荷载作用下的受力分析

通过对某储罐基础在爆炸荷载作用后的现场检测与有限元数值模拟,分析了储罐环形基础在爆炸荷载作用下的受力及变形情况,得出储罐在爆炸时引起的冲击力在环形基础外侧产生的较大拉应力是环形基础产生竖向裂纹的直接原因.     

Analytical behavior of eccentrically loaded concrete encased steel columns subjected to standard fire including cooling phase

A nonlinear 3-D finite element analysis (FEA) model was developed to predict the behavior of eccentrically loaded concrete encased steel (CES) columns subjected to ISO-834 standard fire including heating and cooling phases. The finite element model has been validated against published tests conducted at elevated temperatures. Comparisons between the predicted results and the test results show that this model can accurately predict the behavior of CES columns under fire. The FEA model was then used to investigate the typical temperature-time curve and mid-height lateral deformation-time curve of eccentric compression CES columns in a complete loading history including initial loading, heating and cooling. It is shown that the temperature delay is obvious at the inner layers of concrete. The fire resistance of a CES column should be checked for the full process of fire exposure until temperatures everywhere in the column start to decrease. The lateral deformation of the column still gradually increases during the cooling phase and the column may fail during that phase. There is a large residual deformation after the fire exposure. Furthermore, the variables that influence the behavior of the CES columns under fire were investigated in parametric studies. It is found that the main parameters which influence the lateral deformation-time curve of the column during the full process of fire exposure are load ratio, slenderness ratio, duration time, depth to width ratio and steel ratio, and the main parameters which influence the residual deformation ratio of the column after fire are load ratio, duration time, cross-sectional depth and steel ratio.     

多元结构坝基双排防渗墙控渗效果试验研究

双排防渗墙已广泛应用于西南地区强弱互层深厚覆盖层地基,但双排防渗墙的间距及布置形式如何选择,控渗效果如何等都值得深入研究。基于非饱和土体渗流理论,以强弱互层深厚覆盖层坝基为研究对象,针对双排防渗墙进行试验研究,得出渗流量和出逸坡降,探讨各布置形式下双排防渗墙的控渗效果。研究表明:"前长后短"、"前短后长"、"前后同长"3种布置形式下总渗流量和出逸坡降都随着间距的增加而降低,"前长后短"、"前后同长"布置形式降低明显。坝体渗流量以间距L=13.2、16.5cm为分界线,先增大后降低;坝基渗流量以间距L=13.5、17.5cm为分界线,先降低后增大。双排防渗墙中深度较大的防渗墙消减的水头更大,两防渗墙深度一致时,前后防渗墙分别消减水头37.5%、50%。当前后防渗墙的深度之和一定时,双排防渗墙采用"前短后长"的布置形式相比采用"前长后短"的布置形式,能更有效降低渗流量和抑制出逸坡降,建议优先采用。     

Improving repair sequence scheduling methods for postdisaster critical infrastructure systems

The recovery process of postdisaster critical infrastructure systems (CISs) includes multiple phases, among which the repair phase usually takes the longest time and contributes the largest to system recovery rapidity and system resilience. This article formulates the repair sequence scheduling problem for damaged CIS components under limited repair resources in a general form, and then proposes two novel heuristic methods to enhance its solution performance. To demonstrate the efficiencies of the two proposed methods, typical existing methods are also briefly introduced for comparison purposes, including three component importance‐based methods (CIBMs), a genetic algorithm‐based method (GABM), a time index‐based heuristic method (TIBHM), and a component index‐based exact solution method (CIBESM). Those methods are separately applied into thousands of damage scenarios for three systems, and are then compared in terms of the optimality gap and the computational cost. Results show that the two proposed methods have significantly better performance than existing methods, whereas the first proposed method can be adapted for critical time points‐based resilience assessment and optimization, and the second proposed method can be applied to the recovery of large‐scale CISs with extensive disruptions.     

Z形截面柱抗剪性能试验研究

对Z形截面柱进行抗剪承载力试验,通过分析试验过程中构件裂缝的开展、破坏的形态等试验现象,探索了Z形截面柱受剪破坏机理及受剪破坏规律,得到了轴压比、剪跨比、配箍率以及肢高厚比等因子对试件延性性能和抗剪承载力影响规律,并在试验结果的基础上,给出Z形截面柱抗剪承载力回归公式和可用于工程设计使用的抗剪承载力计算公式,并给出若干工程设计建议,供设计人员参考。     

3140型压阻式微硅加速度计测试与分析

微型加速度计作为一种新型惯性传感器,它在体积、重量、成本、功耗、可靠性和寿命方面都具有传统加速计无可比拟的优势,３１４０型压阻式微硅加速度计是美国ＩＣＳｅｎｓｏｒｓ公司的产品。文中介绍了它的结构设计和工作原理,并对其重要性能参数进行了测试和分析。     

一种新的瞬时测速方法

提出一种基于８０３１单片机的高速冲击缸活塞运动瞬时测速方法,并对其运动参数的测试问题进行了研究,可以精确测量出高速气缸活塞杆的瞬时速度,并可应用于其它类似的测速问题中。     

煤矿粉尘防治技术创新的思考

通过对目前国内煤矿井下综放、综掘工作面和地面洗选煤厂皮带走廊存在的粉尘防治问题及国外煤矿粉尘防治技术管理模式的探讨分析 ,提出了国内煤矿高产高效综放工作面粉尘防治技术的专题研究和粉尘防治技术方法创新的思路和建议     

峰后砂岩非Darcy流渗透特性的试验研究

研究高应力状态下，尤其是峰后低围压下岩石的渗透性具有十分重要的现实意义。利用获得专利权的岩石渗透试验装置与MTS815．02岩石力学伺服试验系统相配套，用来测试单轴峰后给定应变状态下岩样的非Darcy流渗透特性。在阐述岩石Darcy流渗透性的测试原理及误差的基础上，介绍了峰后岩石非Darcy流渗透特性的测试原理、试验系统与测试方案，并给出峰后中砂岩非Darcy渗透特性的试验结果。试验数据表明，单轴峰后应力状态下中砂岩的渗透率k与峰前比较有量级增加，峰后k值随轴向应变ε增长呈二次抛物线关系。