## 4 Analysis of Optimization Results
### Dynamic Optimization of Construction Time-Cost and Result Analysis  
The annual interest rate of the project loan is 6%. By incorporating project parameter information into Equations (6) and (7) and using MATLAB programming, the dynamic optimization of time-cost is carried out based on the genetic algorithm. After 1200 iterations, the optimal solution is obtained by satisfying the termination conditions. Figure 4 shows the minimum and mean values of the population for each iteration, and the convergence of the calculation results is good. Table 2 shows the optimization results, with multiple  
Figure 3: Time-cost optimization process.  
critical paths. The optimal present value of the total cost of the deep excavation project is 6.3938 million yuan, and the present value of direct costs is 5.6295 million yuan. The optimal construction time is 108 days.  
(1) Comparing Figure 1, Tables 1 and 2, the time of each work is between the normal and limit values, and critical work is not compressed into non-critical work. The method of searching for the optimal solution using genetic algorithm is in line with engineering practice and basic assumptions, and the results obtained are true and reliable.  
(2) The total cost of optimization is increased from 6.5033 million yuan to 6.3938 million yuan, and the construction time is changed from 118 days to 108 days. The construction time is shortened by 10 days, and the total cost is reduced by 109,500 yuan. The optimization effect is good. Some individuals in each generation of population are close to or equal to the optimal solution, which is a feasible solution for project implementation and can be selected based on engineering practice.  
According to the optimization results, the network diagram file, 3D site layout model file, and pricing file are adjusted and imported into the BIM5D construction management platform to simulate the construction process. The optimized plan runs smoothly, with no conflicts in various work arrangements, and the construction progress is reasonable and feasible.  
(1) In the optimal solution network diagram, the key line route is changed from one to multiple, and the original key line remains unchanged, which conforms to the basic assumption. The optimization plan reached its peak on the 19 th to 21 st day of construction, with a total daily capital demand of 127,000 yuan. Based on the analysis of the project site situation, various resources and funding supply of the project can meet the needs of the optimized solution.  
(2) After dynamic optimization, the unbalanced coefficient of fund demand changes from 2.08 to 2.16. The peak value of the fund demand curve before and after optimization does not change much, but the number of key routes increases, making project management more difficult. During the implementation of the project, the BIM5D construction management platform is used to monitor the progress of the project in real-time and verify  
Figure 4: Optimal solution and mean value of each generation of population.  
the allocation of project resources and construction costs. Any deviations are identified and adjusted in a timely manner to ensure progress.