2.3.5 Goh’s method
Considering the influence of clay thickness，wall embedment depth and wall stiffness，Goh（1994）carried out a large number of parametric FE analyses and developed a simple design procedure to estimate Fb，the equation is given：
where
H＝excavation depth；
γ＝unit weight of the soil；
su＝undrained shear strength of the clay；
Nh＝modified bearing capacity factor，which can be found in Figure 2.12（a）；
μt＝clay thickness modification factor，which can be found in Figure 2.12（b）；
μd＝wall embedment modification factor，which can be found in Figure 2.12（c）；
μw＝wall stiffness modification factor，which can be found in Figure 2.12（d）.
Figure 2.12 Goh’s design charts
However，the parametric analyses only investigate the wide excavations under plane strain condition，so the proposed method is only reliable when the excavation is long（L≫B）and wide（B／H＞1）.