单轴与围压状态下预拌料混凝土动力学特性试验研究

发布时间：2018-03-29 18:48

本文选题：预拌料混凝土　切入点：含水率　出处：《安徽理工大学》2017年硕士论文

【摘要】：矿井巷道爆破开挖冲击荷载会造成井巷混凝土支护破坏。研究预拌料混凝土冲击动力学特性,对保证井巷安全生产具有重要的工程意义。采用理论和试验相结合的方法,研究了砂子含水率为0%、1.0%、1.5%、2.0%,贮存期为Od、3d、7d、15d、20d、30d预拌料制成的预拌料混凝土在单轴与围压状态下的动力学特性,并对比分析。预拌料混凝土单轴冲击试验结果表明,应力峰值随着预拌料贮存期和含水率的增加而减小。冲击气压越大,其单轴冲击峰值应力越大,预拌料砂子含水率为1.0%、贮存期为3d时的应力峰值最大,冲击气压在0.6MPa和0.9MPa时的峰值应力分别为35.4MPa和48.9Mpa,冲击气压0.9MPa为0.6MPa峰值应力的1.3倍。当预拌料砂子含水率为1.0%、贮存期在3d以内时,其峰值应力达到了 C30混凝土静态抗压强度要求。预拌料混凝土被动围压状态下冲击试验结果表明,其应力峰值随着预拌料贮存期和含水率的增加而减小。不考虑预拌料贮存期0天含水率为0%组,预拌料贮存期为3d,含水率为1.0%时其应力峰值最大,峰值应力为58.3MPa。预拌料含水率为1.0%贮存期少于7d时,其应力峰值变化不大。预拌料贮存期在30d以内的应力峰值均满足C30混凝土静态抗压强度标准值30MPa要求。冲击气压越大,被动围压下预拌料混凝土的冲击峰值应力越大,预拌料混凝土在冲击气压为0.9MPa下冲击强度应力峰值约为冲击气压为0.6MPa时冲击应力峰值的1.7倍。在单轴和被动围压状态下,预拌料混凝土冲击应力峰值均随预拌料含水率和贮存期增加而减小。被动围压对预拌料混凝土的冲击应力峰值有加强作用,预拌料混凝土在有围压状态下的冲击应力峰值约为无围压状态下冲击应力峰值的1.5倍。
[Abstract]:The impact load of blasting excavation in mine roadway will cause damage to concrete support in roadway. It is of great engineering significance to study the impact dynamic characteristics of ready-mixed concrete in order to ensure the safe production of roadway. The method of combining theory with test is adopted. The dynamic characteristics of premixed concrete made of sand with water content of 0 and 1.0 and 1.5 and 2.0, and storage life of Od3 days, 7 days, 15 days and 20 days or 30 days, under uniaxial and confining pressure conditions are studied, and the results of uniaxial impact test of premixed concrete show that the dynamic characteristics of the premixed concrete under uniaxial and confining pressure are compared and analyzed. The peak stress decreases with the increase of storage life and moisture content of premixed materials. The higher the impact pressure, the greater the peak stress of uniaxial impact, the moisture content of sand is 1.0, and the maximum stress peak is when the storage life is 3 days. The peak stress of impact pressure at 0.6MPa and 0.9MPa is 35.4MPa and 48.9 Mpa.The impact pressure 0.9MPa is 1.3 times of the peak stress of 0.6MPa. When the moisture content of ready mixed sand is 1.0, the storage life is less than 3 days. The peak stress meets the static compressive strength requirement of C30 concrete. The impact test results of premixed concrete under passive confining pressure show that, The stress peak value decreases with the increase of the storage life and moisture content of the ready-mixed material. The maximum stress peak value is obtained when the storage life of the ready-mixed material is 3 days and the moisture content is 1.0, without considering the group of 0% water content in the 0 day storage period of the ready-mixed material, and when the storage life of the ready-mixed material is 3 days, and the moisture content is 1.0. The peak stress is 58.3 MPA. When the moisture content of premixed material is 1.0% storage life less than 7 days, the peak stress value changes little. The stress peak value within 30 days of pre-mixed material storage life all meet the 30MPa requirement of static compressive strength of C30 concrete. The higher the impact pressure is, the higher the stress peak value is. Under passive confining pressure, the maximum impact stress of ready-mixed concrete is about 1.7 times that of 0.6MPa at impact pressure of 0.9MPa. Under uniaxial and passive confining pressure, the peak value of impact stress of ready-mixed concrete is about 1.7 times that of 0.6MPa. The peak value of impact stress of ready-mixed concrete decreases with the increase of moisture content and storage life of ready-mixed concrete. Passive confining pressure can strengthen the peak of impact stress of ready-mixed concrete. The peak value of impact stress of ready-mixed concrete under confining pressure is about 1.5 times of that under no confining pressure.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.52

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