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主应力及其方向余弦计算的进一步研究 被引量:3
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作者 王凯 《重庆交通大学学报(自然科学版)》 CAS CSCD 北大核心 2019年第11期58-62,共5页
国内外计算主应力及其方向余弦有两种方法:计算公式法和雅可比方法。首先介绍线性代数中特征值和特征向呈的计算以及弹性力学中主应力及其方向余弦的计算,通过二祥的对比论述了两种方法的数学渊源并且发现:目前采用计算公式法或雅可比... 国内外计算主应力及其方向余弦有两种方法:计算公式法和雅可比方法。首先介绍线性代数中特征值和特征向呈的计算以及弹性力学中主应力及其方向余弦的计算,通过二祥的对比论述了两种方法的数学渊源并且发现:目前采用计算公式法或雅可比方法计算主应力方向余弦,实际上均只计算了两组主应力方向余弦解答中的一组解答,只有将另一组解答补齐,才能得到完整的计算结果。其次利用笔者编写的N层弹性体系力学计算程序NESCP中的计算公式法和国际上著名的BISAR计算机程序中的雅可比方法对各种力学状况下的几十个算例进行了数值计算并列出了4个算例。计算结果表明:在各种力学状况下两种方法的计算结果十分接近,无论是采用计算公式法或是采用雅可比方法均能得到足够精确的主应力及其方向余弦的计算结果。 展开更多
关键词 道路工程 主应力 方向余弦 计算公式法 雅可比方 特征值 特征向量
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将净利润调节为经营活动现金流量净额的三种方法 被引量:1
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作者 温玉彪 《会计之友》 北大核心 2008年第36期103-104,共2页
利润表中的净利润是企业三种活动共同作用的结果,是会计人员依据权责发生制的原则计算出来的;而现金流量表主表中的经营活动现金流量是会计人员按照收付实现制的原则计算得出来的。当利润表中的净利润与现金流量表主表中的经营活动现金... 利润表中的净利润是企业三种活动共同作用的结果,是会计人员依据权责发生制的原则计算出来的;而现金流量表主表中的经营活动现金流量是会计人员按照收付实现制的原则计算得出来的。当利润表中的净利润与现金流量表主表中的经营活动现金流量净额不相等时,应将净利润调节为经营活动现金流量净额。这里介绍三种不同的调节方法与广大读者商榷。 展开更多
关键词 计算公式调节 单项业务调节 会计报表调节
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Rock burst induced by roof breakage and its prevention 被引量:12
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作者 何江 窦林名 +2 位作者 曹安业 巩思园 吕建为 《Journal of Central South University》 SCIE EI CAS 2012年第4期1086-1091,共6页
Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage (RBRB) was proposed a... Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage (RBRB) was proposed and the model was built. Through the model, a method calculating the varied stresses induced by roof breakage in support objects and coal body was proposed and a unified formula was derived for the calculation of stress increment on support objects and coal body under different breaking forms of roof. Whilst the formula for calculating dynamic load was derived by introducing dynamic index Kd. The formula was verified in Huating Mine by stress measurement. According to the formula for stress increment calculating, the sensitivities of dynamic load parameters were further studied. The results show that the thickness and breaking depth of roof, width of support objeet are the sensitive factors. Based on the discussion of the model, six associated effective methods for rock burst prevention are obtained. 展开更多
关键词 roof breakage dynamic load stress increment rock burst mining engineering
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A new method determining safe thickness of karst cave roof under pile tip 被引量:21
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作者 蒋冲 刘浪 吴均平 《Journal of Central South University》 SCIE EI CAS 2014年第3期1190-1196,共7页
Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. ... Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. Firstly the mechanical model to analysis the stability of cave roof under pile tip is founded aiming to solve the problems that the simplified mechanical model has. Secondly, the boundary of cave roof is simply supposed to be supported according to the integrity of the rock mass in the boundary of cave roof. Thirdly, based on the theory of plates and shells, the simplified model is calculated and the theoretical calculation formula to determine the safe thickness of cave roof under pile tip can be obtained when the edges of the cave roof are simply supported. In the end, the analysis of the practical engineering project proves the feasibility and the rationality of the method which can be a new method to calculate the safe thickness of cave roof under pile tip. 展开更多
关键词 KARST cave roof theory of plates and shells PILE safe thickness
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