1. Assistant Professor, Dept. of Civil Engineering, Suzhou Univ. of Science and Technology, Suzhou, Jiangsu 215009, China (corresponding author).
2. Assistant Professor, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto 615-840, Japan.
3. Associate Professor, Dept. of Transport and Civil Engineering, Nanjing Forestry Univ., Nanjing, Jiangsu 210037, China.
4. Civil Engineer, Hanshin Expressway Ltd., 4-1-3 Kyutaro-machi, Chuo-ku, Osaka 541-0056, Japan.
5. Professor, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto 615-840, Japan.