# The Curing and Strength Properties of Highly Moist Waste Mud from Slurry Shield Tunnel Construction
## 3 Results
### Strength Properties Analysis
#### 3.1.2 Compressive Strength Properties of Solidified Soil  
(1) Effect of cement content  
The variation of compressive strength with cement content is shown in Figure 6. The compressive strength of cement solidified and RCSLP solidified soils increases in the form of a power function. The relationship between the compressive strength of cement solidified soil \(R_{1}\) and cement content \(\omega_{cament}\) can be expressed as:  
\[R_{1}=5.053(\omega_{cament})^{1.444} \tag{3}\]  
The relationship between the compressive strength of RCSLP solidified soil \(R_{2}\) and cement content \(\omega_{cament}\) can be expressed as:  
\[R_{2}=20.784(\omega_{cament})^{1.383} \tag{4}\]  
As the cement content increases from 10% to 20%, the compressive strength of the cement solidified soil increases from 135 kPa to 376 kPa, and the compressive strength of the RCSLP solidified soil increases from 492 kPa to 1291 kPa. Compared with the cement solidified soil, the compressive strength of the RCSLP solidified soil increased by 3.64 times and 3.42 times, respectively. Therefore, the compressive strength growth rate of the RCSLP solidified soil is much higher than that of the cement solidified soil, and the RCSLP curing agent can significantly enhance the compressive strength of the solidified soil. Figure 6: Compressive strength variation of solidified soil with cement content. The compressive strength ratio variation of the solidified soil with cement content is shown in Figure 7. The compressive strength ratio of the solidified soil also increases in the form of a power function. The fitting curve correlation coefficient of the strength ratio of cement solidified soil is 0.996, and that of the RCSLP solidified soil is 0.993. Compared with the cement solidified soil, the strength ratio of the RCSLP solidified soil is relatively smaller, and the compressive strength growth rate is also lower. The reason is that the additive has a great effect at the early stage, and the overall strength of the solidified soil can be improved by changing its early strength. With the additive and cement content of 10%, the compressive strength of the RCSLP solidified soil reaches 492 kPa after 7 days. With the increase in the curing time, cement plays an increasingly important role in strengthening the RCSLP solidified soil. When the cement content exceeds 15%, the compressive strength ratio of the cement solidified soil is higher than that of the RCSLP solidified soil. Therefore, the cement content should be 15%. (2) Effect of additive content  
The compressive strength variation of the RCSLP solidified soil with additive content is shown in Figure 8. With the increase in additive content, the compressive strength \(R_{3}\) of the RCSLP solidified soil increases in the form of a logarithmic function, as shown in Figure 8. The relationship between the compressive strength of the RCSLP solidified soil \(R_{3}\) and additive content \(\omega_{additive}\) is expressed as Equation (5). The correlation coefficient of the fitting curve is 0.995. When the additive content is 7%, the compressive strength of the RCSLP solidified soil is 477 kPa. When the additive content is 18%, the compressive strength of the RCSLP solidified soil is 1234 kPa, increasing by 2.58 times. Therefore, the additive can significantly improve the compressive strength of the solidified soil. From the economic point of view, the optimal mixing ratio of the additive is 12%. \[R_{3}=405.708\ln(\omega_{admixture}-5.049)+203.989 \tag{5}\]  
Figure 7: Compressive strength ratio variation of solidified soil with cement content. (3) Effect of curing time  
The compressive strength variation of the solidified soil with the curing time is shown in Figure 9. With curing time increasing, the compressive strength of the cement solidified soil and the RCSLP solidified soil increases in the form of a logarithmic function.