## 3 Mechanical Parameters of Deep Hole Soil
### Soil Compression Characteristic
 } & \multirow{3}{*}{\(\mathrm{e}_{0}\)} & \multicolumn{3}{c}{**Direct Shear Tests**} & \multicolumn{3}{c}{**High Pressure**} & \multicolumn{3}{c}{**Triaxial Undrained Consolidation Tests**} \\ \cline{3-10}  & & & \(\mathrm{c}\) & \(\mathrm{\varphi}\) & \(\mathrm{C}_{\mathrm{c}}\) & \(\mathrm{C}_{\mathrm{s}}\) & \(\mathrm{c}_{\mathrm{cu}}\) & \(\mathrm{\varphi}_{\mathrm{cu}}\) & \(\mathrm{c}^{\prime}\) & \(\mathrm{\varphi}^{\prime}\) \\ \cline{3-10}  & & & **(kPa)** & **(\({}^{\circ}\))** & & & **(kPa)** & **(\({}^{\circ}\))** & **(kPa)** & **(\({}^{\circ}\))** \\ \hline \(1\) & silt & 0.72 & 10.7 & 24.6 & 0.098 & 0.0015 & & & & & \\ \(2\) & silt & 1.02 & 16.4 & 27.7 & 0.089 & 0.0017 & & & & & \\ \(3\) & clay & 0.89 & 15.3 & 19.2 & 0.152 & 0.0032 & & & & \\ \(4\) & silt & 0.61 & 19.0 & 27.6 & 0.093 & 0.0017 & & & & \\ \(5\) & silt & 0.50 & 46.6 & 36.0 & 0.048 & 0.0010 & & & & \\ \(6\) & silt & 0.70 & & & 0.154 & 0.0030 & 85.0 & 31.5 & 77.5 & 32.2 \\ \(7\) & silt & 0.74 & 4.80 & 26.5 & 0.147 & 0.0019 & & & & \\ \(8\) & silty clay & 0.68 & 40.3 & 25.0 & 0.166 & 0.0018 & 119.5 & 7.10 & & \\ \(9\) & silt & 0.72 & 40.0 & 32.2 & 0.162 & 0.0022 & 90.5 & 23.8 & 50.5 & 29.8 \\ \(10\) & silty clay & 0.62 & 75.2 & 34.6 & 0.129 & 0.0013 & 164.4 & 13.0 & 154.2 & 15.3 \\ \(11\) & clay & 0.69 & 30.1 & 33.4 & 0.132 & 0.0011 & 88.0 & 16.8 & 77.0 & 20.0 \\ \(12\) & clay & 0.75 & 76.6 & 24.1 & 0.144 & 0.0009 & 72.0 & 17.9 & 45.5 & 22.9 \\ \(13\) & clay & 0.76 & 129.7 & 34.9 & 0.12 & 0.0015 & & & & \\ \(14\) & clay & 0.76 & 98.5 & 26.6 & 0.129 & 0.0011 & 134.5 & 15.0 & 103.5 & 20.0 \\ \(15\) & silt & 0.62 & 35.3 & 31.0 & 0.093 & 0.0013 & 84.0 & 26.2 & 71.5 & 27.8 \\ \(16\) & clay \# & 0.83 & 158.5 & 17.9 & 0.107 & 0.0013 & 94.0 & 17.2 & 87.0 & 18.9 \\ \(17\) & clay & 0.62 & 125.0 & 39.8 & 0.091 & 0.0047 & 69.0 & 23.7 & 26.5 & 27.8 \\ \(18\) & silty clay & 0.56 & 103.2 & 35.9 & 0.061 & 0.0009 & 174.0 & 17.9 & 99.5 & 23.9 \\ \(19\) & clay \# & 0.65 & 91.5 & 31.7 & 0.100 & 0.0035 & 130.0 & 16.0 & 111.5 & 17.9 \\ \(20\) & clay \# & 0.63 & 144.9 & 24.8 & 0.057 & 0.0011 & 138.5 & 26.7 & 113.5 & 29.7 \\ \(21\) & clay \# & 0.70 & 79.9 & 42.8 & 0.099 & 0.0017 & 93.5 & 18.5 & 83.5 & 20.6 \\ \(22\) & clay \# & 0.72 & 150.0 & 34.8 & 0.092 & 0.0027 & 51.0 & 19.2 & 45.5 & 20.9 \\ \(23\) & clay \# & 0.58 & 102.7 & 32.1 & 0.102 & 0 [PERSON] et al. (2004) proposed that there was a highly linear relationship between \(C_{\rm c}/e_{0}\) and \(C_{\rm c}\) of Japanese Ariming clay, and it was independent of soil layer sensitivity [33]. [PERSON] et al. (1980) analyzed the relationship between \(C_{\rm c}\) and \(e_{0}\) of the 3 rd and 4 th layers of clay in Shanghai [34]. [PERSON] (1976), [PERSON] (1986) and [PERSON] et al. (1986) gave the empirical formula between \(C_{\rm c}\) and \(e_{0}\) of a certain layer or a certain soil property [35; 36; 37]. As can be seen from Figure 6, there is a linear relationship between \(C_{\rm c}/e_{0}\) and \(C_{\rm c}\), the correlation is independent of soil property and the slope of \(C_{\rm c}/e_{0}\) and \(C_{\rm c}\) is 1.2413. Therefore, we obtained the empirical formula between \(C_{\rm c}\) and \(e_{0}\), which is independent of soil property and burial depth. \[C_{\rm c}/e_{0}=1.2413C_{\rm c}+0.0255\;R^{2}=0.89 \tag{5}\]  
Formula (4) can be used to calculate the initial void ratio of soil after a simple water content test when all test conditions are not available in field operations. Then, from Formula (5), the compression index of soil can be deduced. Based on this, engineers can make a preliminary assessment of the compactness and compression characteristics of the soil. [PERSON] et al. (1977) pointed out that the ratio of \(C_{\rm s}/C_{\rm c}\) was between 0.025 and 0.10 [38]. [PERSON] et al. (2012) concluded that the ratio of \(C_{\rm s}/C_{\rm c}\) in the Beijing plain was between 0.0099 and 0.0108 [39]. In this paper, we also statistically analyzed the ratio in the Zhangjiakou area (Table 4).