## 5 Discussion  
A strong relationship between MCC model parameters and deformation problems has been reported in the literature. A prior study examined the effect of MCC model parameters on the horizontal displacement at the front of the pier improved with drilled grouting piles, revealing a ranking according to the significance of the effect, namely, \(\
u\), \(\lambda\), and \(M\)[71]. Several probabilistic analyses have also studied the effect of the spatial variability of \(\kappa\) and \(M\) on the bearing capacity of foundations [40] and the spatial variability of the individual parameter \(\lambda\) on the consolidation settlement of one-dimensional foundations [39]. However, previous studies have not brought up the results for the particular problem of ground surface settlement induced by embraced excavation. According to this study, for the braced excavation surface settlement caused by drawdown, the settlement is notably influenced by the deformation parameters of the MCC model (typically \(\lambda\) and \(\kappa\)). Both have a significant positive relationship, and \(\kappa\) plays a greater role than \(\lambda\). This finding is inconsistent with previous studies, which have suggested that the effect of different parameters of the MCC model varies for a given engineering problem. A possible explanation can be stated as follows. The soil is initially in a limited state of elasticity. With the decline of the water table, the pore water pressure in the soil decreases, and the effective stress increases, which  
Figure 19: Reliability of ground surface settlement and COV\({}_{\lambda,\kappa}\). Figure 18: Effect of COV\({}_{\lambda,\kappa}\) on the PDF curves of probabilistic analysis of ground surface settlement of the excavation: (**a**) PDF of \(H_{\text{m}}\); (**b**) PDF of \(D^{\prime}_{\text{m}}\). is comparable to loading. However, the strain increment due to loading during this process was dominantly elastic. Therefore, the deformation parameter representing the elastic part, \(\kappa\), has a greater impact than the parameter representing the plastic part, \(\lambda\), during the deformation process. The probabilistic analysis results of this study show that the \(H_{m}\) obtained from all realizations is within the range of 35-70 mm, which matches the range of (0.10%-0.80%)\(h_{e}\) (\(h_{e}\) denotes the excavation depth and is equivalent to 12 m herein) recorded by [PERSON] et al. [72] in Shanghai area, China. In comparison, the analyzed values of \(D^{\prime}{}_{m}\) are in a more extensive range of 5-110 m and are most centralized in the 20-35 m interval, more significant than the previously reported levels of (0-1.0)\(h_{e}\) proposed by [PERSON] and [PERSON] [12]. This discrepancy may be due to the hydro-mechanical coupling effect under the drawdown action. [PERSON] et al. [73] also compared the settlement curves considering only excavation versus considering the coupling effect of excavation and draining by FEM analysis. They concluded that the location of the \(D^{\prime}{}_{m}\) of the latter was remarkably greater than that of the former, even greater than twice. With respect to surface settlement influence zoning, a horizontal overview of the current experience provides for two main categories. One category is \(h_{e}\)-related regulations; e.g., [PERSON] et al. [74] proposed that (0-1)\(h_{e}\) is the primary influence zone, (1-2)\(h_{e}\) is the secondary influence zone, and (2-4)\(h_{e}\) is the minor influence zone. This regulation is analogous to the Shanghai technical specification for foundation pit engineering [75] and literature [12]. These regulations are applicable to scenarios considering only excavation, but it is debatable when considering draining scenarios.