白垩系地层冻结砂岩物理力学试验研究
Experimental study on physical mechanics of freezing sandstone of Cretaceous Strata
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摘要: 为进一步认识白垩系地层冻结砂岩的物理力学特性,开展了不同温度状态下饱和中砂岩和粗砂岩的单轴压缩试验,对岩石应力应变状态、破坏形态及对岩石单轴抗压强度、弹性模量进行分析研究。结果表明:随着温度的降低,白垩系地层冻结砂岩单轴抗压强度和弹性模量明显增大,应力-应变曲线的压密段和塑性变形段不明显,表现出明显的弹性和脆性特征;岩样主要破坏形态为劈裂破坏和单斜面剪切破坏,且破坏强度较低;试样的单轴抗压强度值都随温度的降低而不断增大,同一温度状态下,中砂岩单轴抗压强度明显小于粗砂岩,且泊松比随温度的降低而减小,同等温度条件下粗砂岩泊松比小于中砂岩。依据试验结果可为冻结法凿井冻结壁和井壁的设计提供可靠的参数。Abstract: In order to further understand the physical mechanics features of the freezing sandstone in Cretaceous Strata,the uniaxial compression tests of the saturate d medium sandstone and coarse sandstone under the different temperature status were conducted. With the analysis on the rock stress and strain status and the failure m ode,the experiment study was conducted on the uniaxial compressive strength and elastic modulus. The results showed that with the temperature dropped,the uniaxial com pressive strength and elastic modulus of the freezing Cretaceous rock would be increased obviously. The compaction section and plastic deformation section of the stress- strain curve would be more and more not obvious and the more clear elastic and fragility features would be appeared. The major failure mode of the rock samples was a sp lit failure and monoclinic shearing failure and the failure strength was relatively low. The uniaxial compressive strength values of the samples would continuously increased with the temperature reduced. Under the same temperature status,the uniaxial compressive strength of the medium sandstone would be obviously lower than the coarse sa ndstone. The Poisson Ratio would be reduced with the temperature reduced. Under the same temperature,the coarse sandstone would be lower than medium sandstone. T he rest results could provide the references to the design parameters of the freezing wall and mine shaft liner for the mine freezing shaft sinking.