吉林大学学报(地球科学版)
吉林大學學報(地毬科學版)
길림대학학보(지구과학판)
JOURNAL OF JILIN UNIVERSITY(EARTH SCIENCE EDITION)
2014年
1期
249-258
,共10页
苏生瑞%李鹏%王琦%苏卫卫%张莹
囌生瑞%李鵬%王琦%囌衛衛%張瑩
소생서%리붕%왕기%소위위%장형
叠瓦状逆断层%龙门山%地应力%模拟试验
疊瓦狀逆斷層%龍門山%地應力%模擬試驗
첩와상역단층%룡문산%지응력%모의시험
imbricated thrust fault%Longmenshan%crustal stress%simulation experiment
为了揭示叠瓦状逆断层在地质过程中的变形和应力变化规律,为地震预报和地质灾害防治提供参考,以龙门山断裂带为研究背景,采用大型物理模拟试验,再现了叠瓦状逆断层的演化过程。通过对模型内部位移和应变的实时监测,得出了叠瓦状逆断层的变形和应力分布规律:1)除下伏断层的下盘局部斜向下外,整个构造区的变形以沿断层带斜向上为主;断层带同侧,变形量深部大于浅表层;水平向变形随与挤压端距离的增大而逐渐减小,并伴有瞬间的跳跃性增大。2)研究区除在断层上盘的浅层出现局部的拉应力外,其余都处在压应力状态,深部应力及其释放量都大于浅层;应力不是线性的增大或减小,而是随挤压端位移的增大沿某个趋势上下震荡。地应力在下伏断层带附近更容易发生聚积和释放,在变化时间上深部先于浅层。浅层地应力呈现出先增大后减小再增大再减小的规律;深部地应力的释放在上覆断层两侧出现了跳跃性的减小,而下伏断层的两侧先出现瞬时的增大,然后才逐渐减小。3)浅层变形量和应力变化具有相同的规律和同步性,但均滞后于深部应力的变化。
為瞭揭示疊瓦狀逆斷層在地質過程中的變形和應力變化規律,為地震預報和地質災害防治提供參攷,以龍門山斷裂帶為研究揹景,採用大型物理模擬試驗,再現瞭疊瓦狀逆斷層的縯化過程。通過對模型內部位移和應變的實時鑑測,得齣瞭疊瓦狀逆斷層的變形和應力分佈規律:1)除下伏斷層的下盤跼部斜嚮下外,整箇構造區的變形以沿斷層帶斜嚮上為主;斷層帶同側,變形量深部大于淺錶層;水平嚮變形隨與擠壓耑距離的增大而逐漸減小,併伴有瞬間的跳躍性增大。2)研究區除在斷層上盤的淺層齣現跼部的拉應力外,其餘都處在壓應力狀態,深部應力及其釋放量都大于淺層;應力不是線性的增大或減小,而是隨擠壓耑位移的增大沿某箇趨勢上下震盪。地應力在下伏斷層帶附近更容易髮生聚積和釋放,在變化時間上深部先于淺層。淺層地應力呈現齣先增大後減小再增大再減小的規律;深部地應力的釋放在上覆斷層兩側齣現瞭跳躍性的減小,而下伏斷層的兩側先齣現瞬時的增大,然後纔逐漸減小。3)淺層變形量和應力變化具有相同的規律和同步性,但均滯後于深部應力的變化。
위료게시첩와상역단층재지질과정중적변형화응력변화규률,위지진예보화지질재해방치제공삼고,이룡문산단렬대위연구배경,채용대형물리모의시험,재현료첩와상역단층적연화과정。통과대모형내부위이화응변적실시감측,득출료첩와상역단층적변형화응력분포규률:1)제하복단층적하반국부사향하외,정개구조구적변형이연단층대사향상위주;단층대동측,변형량심부대우천표층;수평향변형수여제압단거리적증대이축점감소,병반유순간적도약성증대。2)연구구제재단층상반적천층출현국부적랍응력외,기여도처재압응력상태,심부응력급기석방량도대우천층;응력불시선성적증대혹감소,이시수제압단위이적증대연모개추세상하진탕。지응력재하복단층대부근경용역발생취적화석방,재변화시간상심부선우천층。천층지응력정현출선증대후감소재증대재감소적규률;심부지응력적석방재상복단층량측출현료도약성적감소,이하복단층적량측선출현순시적증대,연후재축점감소。3)천층변형량화응력변화구유상동적규률화동보성,단균체후우심부응력적변화。
Adopting the large physical simulation experiment with the Longmenshan fault zone as the research background ,it reproduced the imbricated thrust fault evolution process .By the real-time monitoring of displacement and strain in inside of the model ,it was concluded the deformation and stress distribution law of imbricate thrust fault as follows :1)The deformation of the whole tectonic region is inclined up along the fault zone except partly inclined down of underlying fault footwall ;the deep deformation is greater than shallow surface at the same side of fault zone ;the horizontal deformation gradually decreases with the increase of the distance from the extrusion end , and accompanied by instaneous jumping increase .2)T he research area is in compressive stress state except local tensile stress in the shallow of the upper wall ,and the deep stress and its release quantity are much greater than the shallow ;the stress does not increase or decrease linearly , but with the increasing displacement of extrusion end along a trend shocks up and down .The crustal stress near the underlying fault zone is more likely to appear accumulation and release .In the changing time ,the deep is jumping decrease ,but the both side of the underlying fault zone instantly increase at first then decrease gradually .3)The deformation and stress of shallow changes with the same rule ,but all are lagging behind the deep .