Physical models of thrust wedges
Physical models of thrust wedges
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DOI：
10.1007/978-94-011-3066-0_6
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Li Huiqi;K. McClay;D. Powell
中科院分区：
文献类型：
--
作者：
Li Huiqi;K. McClay;D. Powell
本文用缩尺砂箱模型模拟了各向同性无粘性和各向异性无粘性介质中临界推力楔的生长和发展过程。系统地研究了层状层序初始厚度的变化、基底拆离的摩擦力和层状体系的各向异性。以前陆冲断系统为主的叠瓦扇发育，与增生棱柱体和前陆褶皱冲断带中的叠瓦扇相似。临界锥形楔接近理论预测的几何形状，是在中间的基础摩擦值（µB= 0.47）下形成的，而在较低的基础摩擦值下，形成的低锥度楔的锥度小于理论预测的锥度。当基础摩擦等于或大于楔中的摩擦系数时，形成超临界楔，并且楔具有更接近建模材料的静止角的高锥度。前陆冲断层的间距/厚度比随地层厚度的增加而增大。逆冲断层的间距随着基底摩擦力的增大而增大。层状系统中较高的基底摩擦力或各向异性有利于沿沿着前陆向逆冲断层位移，并抑制逆冲断层。
Scaled sandbox models have been used to simulate the growth and sequential development of critical thrust wedges in isotropic cohesionless and anisotropic cohesionless materials. Variations in the initial thickness of the layered sequence, the friction of the basal detachment, and the anisotropy of the layered system have been systematically investigated. Imbricate fans of dominantly foreland-vergent thrust systems are developed similar to those found in accretionary prisms and in foreland fold and thrust belts. Critical taper wedges close to theoretically predicted geometries are developed for intermediate values of basal friction (µb= 0.47 whereas for the lower value of basal friction low-taper wedges are formed with tapers less than predicted by theory. Supra-critical wedges are formed when the basal friction equals or is greater than the coefficient of friction in the wedge and the wedge has a high taper closer to the angle of rest for the modelling material. The spacing/thickness ratio of foreland-vergent thrusts increases as the layer thickness increases. The spacing of thrust faults increases with increased basal friction. Higher basal friction or anisotropy within the layered systems favours displacement along foreland-vergent thrusts and suppresses backthrusts.