现代地质
現代地質
현대지질
Geoscience
2015年
4期
755-764
,共10页
周游%李勇%李敬波%邵崇建%颜照坤%闫亮%李辉%王腾文%刘颖倩%陈玮涵
週遊%李勇%李敬波%邵崇建%顏照坤%閆亮%李輝%王騰文%劉穎倩%陳瑋涵
주유%리용%리경파%소숭건%안조곤%염량%리휘%왕등문%류영천%진위함
砂箱模拟%滑脱层%速度场%涡度场%褶皱冲断带%龙门山南段
砂箱模擬%滑脫層%速度場%渦度場%褶皺遲斷帶%龍門山南段
사상모의%활탈층%속도장%와도장%습추충단대%룡문산남단
sandbox modeling%slip layer%velocity field%vorticity field%fold-thrust belt%the southern sec-tion of Longmenshan
在前人对褶皱冲断带的研究基础上,为进一步深入分析对比滑脱层数量、强度、深度等对褶皱冲断带的制约,设计了6组砂箱模拟实验,并运用粒子成像测速(PIV,Particle Image Velocimetry)技术的实时监测,计算出各阶段模型剖面上的速度场和涡度场,对褶皱冲断带的运动学过程和变形机制进行详细刻画和定量分析。实验结果表明,滑脱层的强度和深度均制约着褶皱断层的构造演化,滑脱层的强度越小,其上覆地层中的变形传播越远,滑脱层深度越深,对整个构造样式更具有控制作用,变形也就传播得更远。以微玻璃珠组成的滑脱层主要产生前展型逆冲叠瓦式构造,上部推覆体前缘水平位移较快;以硅胶组成的滑脱层上部形成叠瓦式构造,下部形成冲起构造,上、下两部分具有明显的分层变形特征。PIV监测结果显示,当上盘速度骤停,并且前缘涡度值骤降时,断坡形成并发展成断坪-断坡组合构造样式;下一条断层以相同方式在前缘形成,从而使褶皱冲断带向前陆方向扩展。将实验结果与龙门山南段褶皱冲断带进行了对比分析,得到了较好的印证。
在前人對褶皺遲斷帶的研究基礎上,為進一步深入分析對比滑脫層數量、彊度、深度等對褶皺遲斷帶的製約,設計瞭6組砂箱模擬實驗,併運用粒子成像測速(PIV,Particle Image Velocimetry)技術的實時鑑測,計算齣各階段模型剖麵上的速度場和渦度場,對褶皺遲斷帶的運動學過程和變形機製進行詳細刻畫和定量分析。實驗結果錶明,滑脫層的彊度和深度均製約著褶皺斷層的構造縯化,滑脫層的彊度越小,其上覆地層中的變形傳播越遠,滑脫層深度越深,對整箇構造樣式更具有控製作用,變形也就傳播得更遠。以微玻璃珠組成的滑脫層主要產生前展型逆遲疊瓦式構造,上部推覆體前緣水平位移較快;以硅膠組成的滑脫層上部形成疊瓦式構造,下部形成遲起構造,上、下兩部分具有明顯的分層變形特徵。PIV鑑測結果顯示,噹上盤速度驟停,併且前緣渦度值驟降時,斷坡形成併髮展成斷坪-斷坡組閤構造樣式;下一條斷層以相同方式在前緣形成,從而使褶皺遲斷帶嚮前陸方嚮擴展。將實驗結果與龍門山南段褶皺遲斷帶進行瞭對比分析,得到瞭較好的印證。
재전인대습추충단대적연구기출상,위진일보심입분석대비활탈층수량、강도、심도등대습추충단대적제약,설계료6조사상모의실험,병운용입자성상측속(PIV,Particle Image Velocimetry)기술적실시감측,계산출각계단모형부면상적속도장화와도장,대습추충단대적운동학과정화변형궤제진행상세각화화정량분석。실험결과표명,활탈층적강도화심도균제약착습추단층적구조연화,활탈층적강도월소,기상복지층중적변형전파월원,활탈층심도월심,대정개구조양식경구유공제작용,변형야취전파득경원。이미파리주조성적활탈층주요산생전전형역충첩와식구조,상부추복체전연수평위이교쾌;이규효조성적활탈층상부형성첩와식구조,하부형성충기구조,상、하량부분구유명현적분층변형특정。PIV감측결과현시,당상반속도취정,병차전연와도치취강시,단파형성병발전성단평-단파조합구조양식;하일조단층이상동방식재전연형성,종이사습추충단대향전륙방향확전。장실험결과여룡문산남단습추충단대진행료대비분석,득도료교호적인증。
Based on previous studies,this study used sandbox modeling to analyze the constraint of the number, intensity and depth of slip layers to the fold-thrust belt.Using particle image velocimetry (PIV)as a real-time monitoring technology,six sandbox modeling experiments were designed to calculate the velocity and vorticity of models to quantitative analyze kinematic and deformational mechanism of the fold-thrust belt.The results show that (1 )the strength and depth of slip layers constrain the tectonic evolution of fold faults;(2)the smaller the strength of slip layers is,the farther the deformation propagation of overlying strata is;(3 )the slipping depth is deeper,and the control action on entire structure is larger,thus the deformation spreads farther.The slip layer which is composed of micro-glass beads mainly produces preshow type of thrust imbricate structure,with faster rate of upper horizontal displacement at the nappe front edge.The upper layer which consists of silica gel main-ly generates imbricated structure,with washed form from the lower part of the formation.The upper and lower portions of the slip layer show distinct characteristics of hierarchical deformation.The PIV analysis shows that the ramp off the floor forms and develops into a combination of structural-style ramps when the disk speed arrests and the vorticity of the leading edge rapidly decreases,and the following fault forms in the same manner at the front edge,leading to the forward expansion of the fold-thrust belt.The comparative analysis of the southern section of the Longmenshan fold-thrust belt and experimental results shows good consistency.