摘要:
由于单轴荷载下饱水岩石的动态力学特性与静态力学特性存在很大差异,从宏观上进行力学分析
存在局限性。根据岩石受压全应力应变曲线的细观机制,分析了静态及动态单轴荷载条件下孔隙水影响饱水
岩石裂纹扩展的情况。在静态单轴压缩条件下,初始裂隙受压使自由水产生孔隙水压力,自由水对翼裂纹有
向外挤压的应力,促进裂纹扩展。在动态单轴压缩条件下,自由水会产生粘结力,抑制裂纹扩展。根据翼裂纹
受压扩展原理,推导出饱水单轴条件下动态抗压强度、静态抗压强度的计算公式,在相同断裂韧度下,饱水岩
石静态抗压强度风干岩石静态抗压强度饱水岩石动态抗压强度。对自然风干和饱水砂岩进行单轴静态、
动态压缩实验,结果与理论模型的结果相符。
Abstract:
Dynamicmechanicalpropertiesofwater-saturatedrockunderuniaxialloadarehighlydifferentfromitsstaticmechanicalproperties,
thereasonsofwhichcannotbeexplainedwellbasedon
macro-mechanics.Accordingtomeso-mechanismofrockcompletestress-straincurveunderuniaxial
compression,crackpropagationofwater-saturatedrockinfluencedbyporewaterunderdynamicload
isanalyzedaswellasunderstaticload.Wheninitialfracturesaresubjectedtostaticuniaxialcompressionload,
itcancausefreewatertoappearporewaterpressure,whichcanpromotetheexpansionof
wingedcrackduetoitsextrudingwingedcrackoutwards.Intheconditionofdynamicuniaxialcompressionloads,
freewaterappearcohesiveforcetohinderthepropagationofwingedcrack.Basedon
compressivewingcrackpropagationmechanism,calculationformulasofstaticcompressivestrength
anddynamiccompressivestrengthwithwaterunderuniaxialloadareobtained.Withthesamefracturetoughness,
staticcompressivestrengthofwater-saturatedrockisevenlowerthanthatofdry
rock.Bothofthemarelowerthandynamiccompressivestrengthofwater-saturatedrock.Staticand
impactcompressiveexperimentsonair-driedandwater-saturatedsandstoneareconducted,theexperimentresultsareinagreementwiththeonesfromtheoreticalmodels.
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