Numerical assessment of spacing–burden ratio to effective utilization of explosive energy

The spacing–burden(S/B) ratio plays significant role on rock fragmentation and proper utilization of explosive energy to minimize the undesirable damage.Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes,whereas boulder generations were observed above optimum S/B ratio.Both conditions are not acceptable because of wastage of explosive energy.Therefore,to resolve this issue,a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of explosive energy.Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio.The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak explosive energy.The performance was observed based on peak kinetic energy,peak pressure,radial and hoop stresses on centre of the two blast holes,where pressure rings coalescence.

基于B/S模式的钻井取心数据管理系统的设计与实现

在论述某油田公司钻井取心数据管理系统需求基础上,重点阐述了系统的设计、实现技术和开发过程.同时介绍了Ajax技术在本系统实现中的运用.

基于侧压力系数变异性的隧洞围岩变形响应特征研究

以新疆东天山公路隧道为例,利用三维有限差分数值模拟软件FLAC3D,通过快速应力边界法生成符合实际工况的初始地应力场,结合实际侧压力系数λ的分布,分析λ取0.8、1.0、1.2、1.4、1.6时隧道内部变形规律。结果表明,λ从0.8增至1.6,拱顶竖向变形值减小约16%,拱底竖向变形值减小约14%,拱脚水平变形值增大3倍;在λ较低区段,注意拱顶和拱底处变形,及时安装衬砌系统,建议采取钢支撑挂网喷锚支护,对不稳定块体及时进行锚固;在λ较高区段,注意拱脚处变形,施工时要提高支护强度;在水平方向上一定范围内,由于应力状态的不同,不同沉降值出现逆向增长。