1. Lecturer, School of Civil Engineering, Hefei Univ. of Technology, Tunxi Rd., Hefei 230000, China (corresponding author).
2. Lecturer, School of Marxism, Hefei Univ. of Technology, Tunxi Rd., Hefei 230000, China.
3. Engineer, Maanshan Priority Project Construction Administration Bureau, 138 Huayu Rd., Maanshan 243000, China.