CASE STUDY OF BA-GUAH-SHAN GRAVEL TUNNEL PROGRESSING RATE

• Main Authors: Wei-Ming Hwang, 黃偉明
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/86126143327963884886

碩士 === 朝陽科技大學 === 營建工程系碩士班 === 90 === Many large civil construction projects have been completed or under construction by the government during the past 15 years. The tunnel construction does play a significant role for each transportation projects. Because of the complexity and unpredictable nature of the geology conditions in Taiwan, the circumstance encountered during construction is not easy to predict and evaluate during the planning and design stages. Thus, the schedule and cost of a tunnel construction are hard to control during construction. Therefore, the enhancement on the tunneling construction techniques, understanding the key factor affecting the construction schedule, and the method to improve the construction progress have become the subjects to be overcome for tunnel construction. Most of tunnels constructed either in rocks or soils. For gravel formation, which has properties between rock and soil, is seldom encountered in tunnel. In Taiwan, most work experiences in tunnel had been in rock formation. The experience for the design and construction of the gravel tunnel is still lacking. There is going to have many transportation projects constructed in the gravel formation in Taiwan in the future. Therefore‚how to provide the accumulated experience to the successive construction seems to be an urgent task. Due to the shortage of the data on the construction experience and construction management for tunnel in gravel formation, the Ba-Guah-Shan Tunnel in the Hanbou-Chatoe East-West Expressway is selected as the example in this study. The data of monthly excavation progresses and each construction cycle time are synthesized. The Data for different construction faces and geological classifications are compared and analyzed. The excavation progress in gravel formation is greatly affected by the underground water. To study the influence of many factors, the tunnel is divided into the dry and seepage sections, and east and west bounds’ works, which were constructed by different contractors. The key factors affecting the construction schedule have been found and summarized. The data for work experience and corresponding adjustment to the construction for the gravel tunnel have been accumulated since September 1997. The average monthly progress is about forty meters for each construction cycle. The cycling time is 9 to 14.8 hours. In dry section, the tunnel progressing rate can reach sixty meters or more per month. However, the tunnel construction for dry section, seepage or water flowing section, and sand and silty formations has great difference. Many failures have been encountered in sections of seepage and unconsolidated sandy and silty layers. The progressing rate was reduced to only several meters per month for these sections.