Strength degradation and fracture evolution characteristics of pre-damaged coal samples under unilateral soaking condition

{"Abstract":[0],"With":[1,134],"the":[2,6,16,22,49,55,64,91,112,120,135,140,162,178,185,190,203,230,258,267],"wide":[3],"application":[4],"of":[5,57,96,111,115,137,145,154,165,174,187,205,223,234,240,247,262,271,278],"narrow-coal-pillar":[7],"gob-side":[8,58,263],"entry":[9,59],"retaining":[10,60],"technology":[11,87],"in":[12,37,40],"underground":[13,273],"coal":[14,18,51,97,116,146,157,248,264],"mines,":[15],"narrow":[17,50],"pillars":[19,265],"adjacent":[20,53],"to":[21,54,197,210],"goaf":[23,30,56],"under":[24],"such":[25],"conditions":[26],"are":[27,73,80,99,126],"affected":[28],"by":[29,119],"ponding":[31],"for":[32,257],"a":[33,220,255],"long":[34],"time,":[35],"resulting":[36],"significant":[38],"changes":[39,192,209],"their":[41],"physical":[42],"and":[43,75,88,93,131,142,161,177,189,244,266,269],"mechanical":[44],"properties.":[45],"In":[46],"this":[47],"paper,":[48],"pillar":[52],"is":[61,168],"taken":[62],"as":[63],"research":[65,251],"object.":[66],"Coal":[67],"samples":[68,98,117,147,158],"with":[69,84,184],"different":[70],"pre-damage":[71,138],"levels":[72],"prepared,":[74],"unilateral":[76],"water":[77,274],"immersion":[78],"tests":[79],"carried":[81],"out.":[82],"Combined":[83],"acoustic":[85,175],"emission":[86,176],"fractal":[89,217],"theory,":[90],"strength":[92,141,152],"crack":[94],"evolution":[95,232],"analyzed.":[100],"The":[101,106,150,171,215,250],"results":[102,252],"show":[103],"that:":[104],"(1)":[105],"average":[107],"initial":[108],"damage":[109,122,191,196],"variables":[110],"five":[113],"groups":[114],"calculated":[118],"revised":[121],"variable":[123],"calculation":[124],"method":[125],"0,":[127],"0.135,":[128],"0.141,":[129],"0.157":[130],"0.169;":[132],"(2)":[133],"increase":[136,186],"level,":[139],"elastic":[143,166],"modulus":[144,167],"continuously":[148],"degrade.":[149],"maximum":[151],"reduction":[153],"highly":[155],"damaged":[156,241],"reaches":[159],"39.6%,":[160],"degradation":[163],"range":[164],"37.4%;":[169],"(3)":[170],"peak":[172],"value":[173],"cumulative":[179],"ringing":[180],"count":[181],"gradually":[182],"decrease":[183],"damage,":[188],"from":[193],"brittle":[194],"tensile":[195,211],"ductile":[198],"tensile-shear":[199],"composite":[200],"damage.":[201],"Under":[202],"condition":[204],"high":[206],"pre-damage,":[207],"it":[208],"peeling":[212],"failure;":[213],"(4)":[214],"fracture":[216,236,242],"dimension":[218],"presents":[219],"variation":[221],"trend":[222],"\\"decline—fluctuating":[224],"minimum":[225],"value—rise\\",":[226],"which":[227],"fully":[228],"reflects":[229],"three-stage":[231],"law":[233],"primary":[235],"development,":[237],"directional":[238],"penetration":[239],"surfaces":[243],"scattered":[245],"cracking":[246],"blocks.":[249],"can":[253],"provide":[254],"reference":[256],"long-term":[259],"stability":[260],"evaluation":[261],"prevention":[268],"control":[270],"local":[272],"hazards.":[275],"(":[276],"date":[277],"received":[279],"paper:":[280],")":[281]}