FAQ
EN 1997-1 DA1对边坡稳定性有何规定？+
EN 1997-1 DA1对土体强度应用分项系数。组合2（A2+M2）控制，γφ=1.25，γc=1.25。
毕肖普法和费伦纽斯法有什么区别？+
费伦纽斯法忽略条块间力，通常给出比毕肖普低5-15%的稳定系数。毕肖普简化法推荐用于设计。
孔隙水压力比rᵤ是什么？+
rᵤ = u / (γ × h) 是孔隙水压力与上覆压力的无量纲比值。
拟静力地震分析是如何实现的？+
拟静力方法对每个条块增加水平惯性力Kₕ×W。
边坡稳定系数的要求是什么？+
静态荷载下Fs≥1.5是永久性边坡的标准要求。地震时（拟静力）通常要求Fs≥1.1。
临界滑动面搜索如何工作？+
计算器搜索候选圆心网格，保留具有最小毕肖普稳定系数的圆。
Methodology
Bishop Simplified Method+
Iterative moment-equilibrium method. For each slice i:
m_α = cos(α) + tan(φ_d)·sin(α)/FoS
numerator_i = (c_d·b + W·(1-rᵤ)·tan(φ_d)) / m_α
FoS = Σ[numerator_i] / Σ[W·(sin(α) + Kₕ·cos(α))]
Iterated until ΔFoS < 0.0005. EN 1997-1 DA1 C2 partial factors applied to strength before iteration.
Swedish Slice / Fellenius Method+
Force-equilibrium method, no inter-slice forces:
N_i = W·(cos(α) - Kₕ·sin(α) - rᵤ)
FoS = Σ[c_d·(b/cos(α)) + N_i·tan(φ_d)] / Σ[W·(sin(α) + Kₕ·cos(α))]
More conservative than Bishop (5–15% lower FoS for typical geometries). Used for comparison.
Critical Circle Search+
Grid search over candidate circle centers: xc ∈ [-H/2, 0, H/2, xCrest/2, xCrest], yc ∈ [H, 1.5H, 2H]. Radius set to pass through the toe (0,0): R = √(xc²+yc²). For each candidate, slices are generated and the Bishop FoS computed. The circle yielding the minimum FoS is retained as the critical failure surface.
EN 1997-1 DA1 Partial Factors+
DA1 Combination 2 (A2+M2) governs slope stability:
γφ = 1.25: φ_d = arctan(tan(φ')/1.25)
γc = 1.25: c_d = c'/1.25
Combination 1 (A1+M1): γφ = γc = 1.0 (no reduction). Both combinations are checked; C2 typically governs for typical slopes.