## 2 Construction of Cemented Soft Rock Dams
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & \multirow{2}{*}{**Sandstone**} & \multirow{2}{*}{**Cement** (kg/m\({}^{3}\))**} & \multirow{2}{*}{**Fly Ash** (kg/m\({}^{3}\))**} & \multirow{2}{*}{**CWeb** (kg/m\({}^{3}\))**} & \multirow{2}{*}{**Water-Cement** (kg/m\({}^{3}\))**} & \multirow{2}{*}{**Sand Ratio** (\%)**} & \multirow{2}{*}{**Sand Ratio** (\%)**} & \multirow{2}{*}{**Complexive Strength of** **(MPa)**} & \multirow{2}{*}{**Bulk Density** (kg/m\({}^{3}\))**} \\  & & & & & & & & **28 d** & **180 d** \\ \hline \multirow{2}{*}{\(1\)} & \multirow{2}{*}{\(100\)} & 50 & 50 & 1.6 & 1.0 & 25 & 3 & 4.7 & 2277 \\  & & 60 & 60 & 1.9 & 0.83 & 25 & 3.6 & 5.8 & 2260 \\ \hline \multirow{2}{*}{\(2\)} & \multirow{2}{*}{\(71.25\)} & 60 & 60 & 3.3 & 3.9 & 25 & 3.9 & 7 & – \\  & & 45 & 45 & 5.3 & 1 & 21 & 5.4 & 6.9 & – \\  & & 50 & 50 & 4.2 & 0.9 & 21 & 6.8 & 10.6 & – \\ \multirow{2}{*}{\(3\)} & \multirow{2}{*}{–} & 60 & 60 & 8.6 & 0.8 & 21 & 8.7 & 10.5 & – \\  & & 60 & 60 & 6.1 & 1 & 30 & 5.7 & 8.6 & – \\  & & 70 & 70 & 4 & 0.9 & 30 & 6.1 & 7.9 & – \\ \hline \multirow{2}{*}{\(4\)} & \multirow{2}{*}{\(50\)} & 60 & 60 & 5.6 & 0.71 & 27.8 & 7.4 & 11.4 & 2357 \\  & & 40 & 50 & 50 & 6 & 0.7 & 27.2 & 8.3 & 11.8 & 2403 \\  & & 30 & 60 & 60 & 6.6 & 0.82 & 31.7 & 10.9 & 14.2 & 2436 \\ \hline \multirow{2}{*}{\(5\)} & \multirow{2}{*}{\(40\)} & 55 & 55 & 2 & 0.77 & 25 & 8.3 & 13.1 & 2425 \\  & & 35 & 55 & 55 & 6 & 0.77 & 25 & 9.6 & 14.8 & 2414 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main strength test results of cemented sand and gravel with different types of aggregates. Figure 1: Typical design cross-section of a cemented soft rock dam. The test results of the material properties of other cemented sand and gravel mixes carried out in the field showed that the anti-seepage grade reached the level of W4 and that the frost resistance grade of the 180-day cemented sand and gravel reached F50 due to a lack of air entrainment in the tests, while the frost resistance performance could be improved after air entrainment. The seepage and erosion test results showed that the relatively well compacted cemented sand and gravel had significantly better anti-seepage and erosion performance than poorly compacted or cracked cemented sand and gravel. Therefore, special attention should be paid to the design and construction quality of the anti-seepage system of the cemented sand and gravel dam to address the long-term dam durability problem caused by continuous seepage and erosion of the cemented sand and gravel. The performance test of the cemented gravel material which was soaked in water under changing temperature shows that as long as the specimen was cured in water, it had a good strength even in low-temperature water (0-5 \({}^{\circ}\)C), and there was no loosening phenomenon. However, regardless of whether the materials soaked in water or not, the strength of the specimen decreased under low-temperature and changing temperature conditions. Compared with the standard curing conditions, the average strength of the specimens cured by low-temperature water was reduced by 35% and the strength of specimens with a long curing period was slightly reduced after soaking in water. Therefore, it is necessary to take certain protective measures for wintering during the construction period. (2) Interlayer shear strength of soft rock cementitious material. The shear strength of cemented sand and gravel dams was investigated for the Shoukoubao cemented dam [12] in Shanxi Province and the Xijiang cemented dam [13] in Guizhou Province, among the existing cemented sand and gravel projects, thereby obtaining a number of findings. Nevertheless, the sliding stability-related parameters of soft rock cemented sand and gravel dams after vibratory rolling require experimental analysis. To this end, in situ direct shear tests were carried out on cemented sand and gravel with different contents of soft sandstone.