**3.2 Analysis procedure**

velocity curve, and inverse-velocity curve and, applied to the maintenance methods of the slope. The strength degradation of the soil due to the time-dependent deterioration phenomenon was quantified by SRF. However, geological factors and strength degradation due to groundwater cannot be considered. Therefore, the proposed method in this study cannot be applied when the groundwater level is

In the last section, the results of the slope stability analysis are applied to the maintenance method. A typical sensor used for slope maintenance is an in-site inclinometer, which is applied to SPC using slope stability analysis results at the same point. Next, a mathematical failure model of the slope was predicted using a cumulative displacement curve. And the time of the slope failure was predicted using an inverse-velocity curve and, compared the formulation of Fukuzono [1]. Finally, the collapse behavior of Selborne in the United Kingdom and Kunini Slope

**Figure 2** in this study improves the problem of the slope stability analysis method that only estimates the FOS and, the problem of maintenance method that fails to evaluate clear management criteria and failure behavior of slope. It also combines the advantages of slope stability analysis and maintenance method based on measured data [35, 36]. Slope stability analysis is used to determine the failure behavior and FOS of the slope. And, it can be applied to the maintenance method to predict the management criteria of statistical process control method, a mathemat-

In the maintenance of the slope, the surface displacement is usually tension wire, and the ground displacement is the inclinometer. Because the displacement of the entire slope is analyzed using the FEM, that can be applied to the management criteria of the displacement measuring instrument installed on the slope. In particular, the displacement at the crown of the slope is very important, which can be measured both by tension wire and inclinometer. There are two maintenance methods presented in this study. First, the failure model is calculated by the cumulative displacement curve of the slope. And the displacement according to the depth is applied to the SPC method to judge the occurrence of abnormal behavior of the slope. If only tension wire is applied to the maintenance of the slope, the formation of the failure surface cannot be confirmed because only the surface displacement of the slope can be measured. Because the inclinometer measures the displacement of the whole underground, it has an advantage that it can easily judge the failure surface. Therefore, the inclinometer was applied to the slope instrument in this study. Please refer to KICT

[20] for the advantages and disadvantages of both measurement devices.

located on the predicted failure surface of the slope.

*Mesh and boundary conditions of slope stability analysis.*

**Figure 1.**

*Slope Engineering*

**162**

in Japan, as reported by Petley [34], was compared.

ical failure model of slope, and the time of slope failure.

In this section, detailed description is given for each step according to the flowchart shown in **Figure 2**. The details are as follows:


$$
\sigma'\_f = \frac{c'}{\text{SRF}} \tag{5}
$$

$$\phi\_f' = \tan\left(\frac{\tan\phi'}{SRF}\right)^{-1} \tag{6}$$

the inverse-velocity curve of step 14. Therefore, if the slope failure happens, the measured displacement velocity curve changes into the 1st-degree polynomials. It means the slope displacement velocity turns into invariable velocity, and it is estimated that the slope failure happens. Therefore it could

*Integrated Analysis Method for Stability Analysis and Maintenance of Cut-Slope in Urban*

14. Step 14: This stage predicts the time of slope failure in slope maintenance. Curve fitting is performed by regression analysis of the inverse-velocity curve by slope stability analysis. According to the existing literature, slopes with ductile behaviors are a third polynomial equation and slopes with brittle behavior are a linear equation. Regression analysis results are also compared

**4.1 Generate finite element model for slope stability analysis (step 1** � **10)**

In the first section, the geometric of the slope and the finite element model of FEM are generated. And, to consider the time-dependent deterioration, the SRF is

For the slope stability analysis of the progressive behavior of slope, the geometry and meshes of the finite slope of 10.0 m in height and 1: 1.2 of standard slope were created (**Figure 1**). For this research, the cut-slope modeling is obliged the standard height and incline suggested by the design manuals [19, 38]. The displacements until progressive failure analyzed FEM are compared to the measured data, the

The boundary condition of left and right side is dx = 0 and same as roller. The boundary condition of the floor is dz. = 0, which is the same as the hinge. The load applied only its own gravity. In the finite element model, the element at the point

The Mohr-coulomb model was selected for the FEM for which the internal

weight (γ*t*Þ are needed. Among such factors, the relative importance of the dilatancy angle that reflects the change in volume resulting from the yield process is less significant in the analysis of the stability of slope that calculates the safety factor [11]. In this study, the value of dilatancy angle was set 0° to let the change in volume to be constantly applied to the analysis. The values of the physical proper-

The soil slope behaviors are largely divided into two categories; firstly, ductible behavior in case of small particle soils, at second, brittle behavior in case of coarse particle soils. Mohr-coulomb model is used to analyze those two cases, which is the elastic-perfect plastic model. The case 1 is for the ductile behavior of slope, whose cohesion value is applied as 10 kPa to show the behavior small soil particles. The case 2 is for the brittle behavior of slope, whose cohesion value is 0 kPa to show the

), dilatancy angle (ψÞ, Poisson's ratio (υÞ, and unit

be important criterion for slope maintenance.

*DOI: http://dx.doi.org/10.5772/intechopen.94252*

with Fukuzono [1]'s slope failure prediction formula.

**4. Application result of the integrated analysis method**

applied to the strength parameter of the soil (step 1 � 3).

where the in-place inclinometer is installed should be identified.

*4.1.2 Step 2: Soil parameters of Mohr-coulomb model of solpe*

*4.1.1 Step 1: Generate geometry and mesh of slope*

criteria come from the inclinometer data.

ties of the soil are as summarized in **Table 1**.

brittle slope behavior of coarse soil particles.

**165**

friction angle ∅<sup>0</sup> ð Þ, cohesion (c<sup>0</sup>

where, c0 , *cf* 0 , ϕ<sup>0</sup> , and *ϕ<sup>f</sup>* 0 denote the cohesion, cohesion at the point of failure, internal friction angle, and internal friction angle at the point of failure, respectively. SRF denote the strength reduction factor.


*Integrated Analysis Method for Stability Analysis and Maintenance of Cut-Slope in Urban DOI: http://dx.doi.org/10.5772/intechopen.94252*

the inverse-velocity curve of step 14. Therefore, if the slope failure happens, the measured displacement velocity curve changes into the 1st-degree polynomials. It means the slope displacement velocity turns into invariable velocity, and it is estimated that the slope failure happens. Therefore it could be important criterion for slope maintenance.

14. Step 14: This stage predicts the time of slope failure in slope maintenance. Curve fitting is performed by regression analysis of the inverse-velocity curve by slope stability analysis. According to the existing literature, slopes with ductile behaviors are a third polynomial equation and slopes with brittle behavior are a linear equation. Regression analysis results are also compared with Fukuzono [1]'s slope failure prediction formula.
