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土工布环向约束球形鼓胀变形及破坏特性分析 被引量:1
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作者 韩瑞晨 薛霞 +1 位作者 李辰 李旺林 《工程科学与技术》 EI CSCD 北大核心 2023年第2期267-274,共8页
复合土工膜由土工膜和土工布组成,在平原水库防渗中,土工布起保护加强作用,并对复合土工膜鼓胀变形有重要影响。本文将土工布气胀现象简化为环向约束球形鼓胀变形模型,借助土工布布下铺设的不透气薄膜,通过鼓胀变形专门试验设备,进行鼓... 复合土工膜由土工膜和土工布组成,在平原水库防渗中,土工布起保护加强作用,并对复合土工膜鼓胀变形有重要影响。本文将土工布气胀现象简化为环向约束球形鼓胀变形模型,借助土工布布下铺设的不透气薄膜,通过鼓胀变形专门试验设备,进行鼓胀变形试验,研究土工布鼓胀的变形特征和力学特性,并借助显微镜着重分析土工布变形过程中纤维结构变化过程和胀破机理。结果表明:(1)土工膜胀破压力约为土工布胀破压力的50%~60%,可见膜上土工布除起保护作用外,还会对土工膜变形产生约束作用,并增加其抵抗变形的能力。(2)土工布在鼓胀变形中,张应力–应变曲线表现为塑性变形特征,可分为线弹性、屈服、强化和胀破拉断共4个阶段。(3)土工布鼓胀变形形状为半球状,撕裂点一般出现在冠顶处,且进一步扩展为纺锤形撕裂破坏;微观结构分析表明,针刺短纤维形成的缠结点具有一定的缠结力,缠结点之间的纤维具有一定的拉伸强度,缠结点缠结力逐渐失效和纤维断裂是土工布鼓胀变形破坏的主要原因。(4)土工布单位面积质量越大,纤维和缠结点越密,可承受的鼓胀压力越大,即抵抗鼓胀变形的能力越强。研究成果对于分析膜上土工布对土工膜鼓胀变形强度的贡献具有一定实际意义。 展开更多
关键词 土工布 变形 胀破分析 力学特性 纤维 缠结点
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Swelling and breaking characteristics of limestone under high temperatures 被引量:5
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作者 CHEN Lun-jian HE Jun +1 位作者 CHAO Jun-qi QIN Ben-dong 《Mining Science and Technology》 EI CAS 2009年第4期503-507,共5页
The elemental composition,heat expansibility and breaking characteristics of limestone have been investigated with the use of an energy spectrum analyzer,a SEM,an optical microscope and an experimental heat swelling p... The elemental composition,heat expansibility and breaking characteristics of limestone have been investigated with the use of an energy spectrum analyzer,a SEM,an optical microscope and an experimental heat swelling power system.The results show that 1) the heat expansibility of limestone has anisotropic properties,and 2) the heat expansion rate in the direction perpendicular to stratification is eight times greater than the rate parallel to stratification.The changes in heat expansibility as a function of heating temperature is essentially coincident with that of swelling and breaking of mineral particles and the appearance of cracks,indicating that the reason for causing the heat expansion of rock are the structural changes of limestone caused by thermal stress,crystal transformation and mineral decomposition.The apparent destruction of limestone under high temperatures is largely characterized by rock stratification breaks.When the limestone is heated beyond a certain limit,the rock destroys into crazed cracks. 展开更多
关键词 LIMESTONE high temperature EXPANSIBILITY
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