|Shield Tunnel Completion of“Zhongli ~ Wuquan ~Qingpu & Zhongli~ Songshu 2 circuits in and out to Wuling 161kV Undergroun|
“Zhongli ~ Wuquan ~Qingpu & Zhongli~ Songshu 2 circuits in and out to Wuling 161kV Underground Tunnel Turnkey Engineering” is one of TPC “The 7th transmission plan in 2010~2011” projects.
This project provides the power demand for Taoyuan International Airport MRT line.
The scope includes the underground pipeline∮8”, the structure of shaft # 1, # 2A, # 2B, # 3, shaft electrical equipment installation, shielding tunnel between # 2B ~ # 3 ∮ 3.5m in inter diameter, 550m in length.
Shield tunnel machines consists of the cut head, ring girder, screw machine, and concrete segment assembly machines, and the total weight is about 127 tons.
Considering the surrounding space, safety and work area, we use the mobile crane in the capacity 1000 tones to lift the shield tunnel machine to the bottom of shaft.
Before boring, visual inspection of shield tunnel machine was performed with TPC to inspect the body length, diameter. Then testing the operation function of the cut head, screw machine, concrete segment assembly machines, and hydraulic jack.
To avoid the water seepage when breaking the mirror face, to perform the soil sampling to test permeability coefficient and soil compression strength after performing the soil consolidation.
Prior to the commencement of shield tunnel, we perform the geological prospecting to conduct the soil analysis to evaluate the cut head type of shield tunnel machine in accordance with the TPC specification.
But the soil sample cannot be fully reflected the actual soil condition. The actual gravel size after digging of shield tunnel machine is 60cm ~ 90cm exceeds the initial soil sampling 60cm. It was usually caused the progress stopping of shield tunnel machine due to the sticking of huge gravel. And it also needs 3~5 days for maintenance and troubleshooting per time.
Fortunately, under the successful collaboration with the site members, the initial excavation was completed during Jan. to Apr. 2011, normal excavation was completed during May to Oct. 2011
It is a progressive step for accumulating the experience of construction and management.