Microbial-induced　calcite　precipitation(MICP)　is　a　good　approach　for　cementing　residual　soil　to　the　bio-claystone　with　high　strength,　and　hence,　is　widely　applied　in　the　subgrade　improvement.　However,　the　durability　of　the　bio-claystone　in　the　frozen　regions　is　still　uncharted.　Therefore,　it　is　necessary　to　study　damage　characteristics　of　the　bio-claystone　under　freezing-thawing　cycles,　which　will　provide　references　for　the　further　engineering　application　of　MICP.　Samples　of　the　bio-claystone　of　shale　residual　soil　were　prepared　after　grouting　period　and　rate　were　determined,　and　freezing-thawing　tests　with　different　moistures　were　performed.　The　damage　characteristics　and　epigenetic　features　of　the　bio-claystone　samples　were　analyzed,　and　the　developing　process　of　internal　pore　and　fissure　of　the　bio-claystone　was　investigated　using　the　nuclear　magnetic　resonance(NMR).　It　is　shown　that　the　damage　of　the　bio-claystone　under　freezing-thawing　cycles　is　resulted　from　that　the　frost　heave　force　of　pore　water　exceeds　the　bond　strength　of　MICP.　Clastic　particles　fall　down　from　the　surface　of　samples　due　to　the　invalidation　of　cementation,　and　the　damage　area　increases　with　increasing　the　water　content　and　the　number　of　cycles.　T2　spectral　curves　of　the　bio-claystone　remarkably　vary　with　different　water　contents.　The　development　of　the　internal　crack　of　the　bio-claystone　can　be　evaluated　by　analyzing　waveform　alteration　with　cycles.　It　is　also　indicated　that　lower　moisture　causes　the　development　of　medium　and　small　fissures　while　that　higher　moisture　results　in　the　continuous　expansion　of　large　fissures.　The　destruction　of　the　bio-claystone　gradually　develops　from　the　central　part　to　both　ends　of　the　sample.　With　the　increment　of　the　cycle　number,　the　growth　rate　of　large　fractures　in　the　central　part　of　the　sample　is　greater　than　that　at　both　ends.　In　the　initial　stage,　the　＇sharp　point＇　effect　occurs　in　the　middle　of　the　T2　curve　with　high　moisture.　With　increasing　cycles,　however,　the　＇sharp　point＇　gradually　disappears　and　the　curve　becomes　flat.　Large　fractures　expand　from　the　central　part　to　both　ends　and　then　penetrat　gradually,　which　finally　causes　the　failure　of　the　bio-claystone.　©　2018,　Science　Press.　All　right　reserved.