## 5 Benefits Study
### Ecological Benefits Analysis  
In the context of China's efforts to reduce carbon emissions, the construction industry has become a key component in helping to achieve China's \"emission peak and carbon neutrality\" goals. The construction of road foundations consumes a large amount of non-renewable resources, the extraction, burning and emission of which can have a significant impact on the ecological environment. Therefore, in this paper, we decided to use carbon emissions as a parameter to calculate and compare Schemes I and 2, and then choose a more reasonable construction scheme.  
It is complex to determine all environmental impacts based on whole process life cycle assessment (LCA) theory, so this paper chooses to use a simplified carbon emission assessment model [15, 33, 34], which mainly considers carbon emissions during the material production, transportation and construction phases, with the whole life cycle process shown in Figure 6 and the mathematical model for calculation shown in Formula (10).  
\[E=E_{p}+E_{t}+E_{c}, \tag{10}\]  
where \(E\) represents total carbon emissions over the life cycle; \(E_{p}\) represents carbon emissions from the production of building materials; \(E_{t}\) represents carbon emissions from the transportation phase of building materials; and \(E_{c}\) represents carbon emissions from on-site construction.  
Carbon emissions in the materialization phase are shown in Formula (11) [16]. Building materials are transported from the production site or sales vary to the construction site by  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Single Project** & **Scheme I/CNY** & **Scheme II/CNY** \\ \hline earthworks & 866,097.355 & 682,558.62 \\ plain concrete piles & 2,908,879.97 & \\ CFG piles & 287,922 & \\ cement mixing piles & 551,403.73 & \\ sand and gravel bedding & 1,181,795.615 & \\ steel-plastic grating & 718,177.85 & \\ plastic drainage board & 102,693.481 & \\ cast-in-place cover slab C35 concrete & 1,021,311.35 & \\ Cast-in-place cover reinforcement & 1,004,711.87 & \\ FLC & & 6,749,642.1 \\ clay borders & & 142,409 \\ Total & 816,421,993.221 & 7,574,609.72 \\ \hline \hline \end{tabular}
\end{table}
Table 6: The specific cost of the construction plan.  
Figure 6: Life-cycle carbon emissions flow chart.  
rail, road or water, which consumes fossil energy and produces greenhouse gases. The analysis in this paper assumes that road transport is used (12), which is calculated using the \"process energy\" environmental impact inventory, as shown in the Formula [16]. The energy consumed for the operation of each piece of machinery and equipment during the construction phase is mainly diesel and electricity, and the resulting gas emissions are calculated as shown in Formula (13).  
\[E_{p}=Q_{p}\times M_{p}, \tag{11}\]  
\[E_{t}=D_{t}\times M_{t}, \tag{12}\]  
\[E_{c}=Q_{c}\times K_{c}, \tag{13}\]  
where \(Q_{p}\) denotes the amount of raw materialized blended into building materials, \(M_{p}\) denotes the physical inventory of carbon emissions from the production of raw materials, \(D_{t}\) denotes the transport distance, using the average transport distance of 67 km in China [35], \(M_{t}\) denotes the carbon emission inventory of transporting building materials, \(Q_{c}\) denotes the amount of fuel power used for construction machinery, \(K_{c}\) denotes the carbon emission factor per unit of fuel for machinery.  
Take the cement mix pile calculation as an example. The carbon emission inventories for the materialisation, transportation and construction phases of a unit length of cement mixing pile are shown in Table 7. The results of the calculations for Schemes I and II are shown in Table 8. It is concluded that the carbon emission of Scheme I is about 41,974,810 t and that of Scheme II is about 14,953,161 t. The total carbon emission of Scheme II is about 1/3 of that of Scheme I, and Scheme II has better ecological benefits.