Besides the large-scale wedge shape itself, the most prominent structural feature of accretionary wedges and fold-and-thrust belts is the common pattern of imbricate thrust faults. This study illuminates the fundamental mechanical processes and material properties controlling the width of the crustal blocks bounded by major thrusts using analytical solutions of stress as well as two-dimensional finite-difference models. The numerical models predict that the initial width w₀ of a thrust block is set when that block first forms at the very front of the wedge. The width is found to subsequently decreases approximately in proportion to the mean horizontal strain needed for an ideally triangular-shaped Coulomb wedge with a critical taper. Block width is proportional to the thickness H of the incoming, accreting sediment. A key quantity that influences the normalized initial block width w₀/H is the distance L forward of the frontal thrust needed for the net horizontal force from shear on the base of the incoming sediment to balance the net force on the frontal thrust. It is within this distance where stress in the incoming sediment is substantially elevated and thus where the new frontal thrust forms. Results show that L/H and, correspondingly, w₀/H increase with increasing sediment friction angle ϕ, cohesive strength C₀ and pore-fluid pressure ratio λ, and decrease with increasing basal friction angle ϕ_b and basal dip β. Normalized width is sensitive to ϕ and relatively insensitive to ϕ_b and λ. Results for submarine and subaerial wedges follow the same scaling law. The scaling law relates the observables, w₀/H and β, to the material properties, ϕ, ϕ_b, λ, and therefore provides a theoretical relation that can be used independent of, or together with critical Coulomb wedge theory (CWT) to constrain these properties.

除大型楔形本身外，增生楔和褶皱冲断带最突出的结构特征是岩性逆冲断层的常见模式。这项研究使用应力的解析解以及二维有限差分模型，阐明了控制主推力界定的地壳块宽度的基本力学过程和材料特性。数值模型预测，当推力块首先在楔形的最前面形成时，将设定推力块的初始宽度w ₀。随后发现宽度大约与理想的具有临界锥度的三角形库仑楔所需的平均水平应变成比例地减小。块宽与厚度H成正比进入的，积聚的沉积物。影响归一化初始块宽w ₀ / H的关键因素是前推力的距离L，前推力是净水平力从进入的沉积物底部的剪切力到平衡前推力的净力所需的。在此距离之内，进入的沉积物中的应力显着升高，因此形成了新的前推力。结果表明，L / H和相应的w ₀ / H随着泥沙摩擦角ϕ，内聚强度C ₀和孔隙流体压力比λ的增加而增加，并随着基底摩擦角ϕ _b和基底倾角β的增大而减小。归一化的宽敏感φ和相对不敏感的φ _b和λ。水下和空中楔形物的结果遵循相同的比例定律。比例定律将可观测值w ₀ / H和β与材料特性ϕ，ϕ _b，λ关联，因此提供了一种理论关系，可以独立于临界库仑楔理论（CWT）使用，也可以与临界库仑楔理论一起使用限制这些属性。