Influence of Construction Cracks on Seepage Characteristics of River Embankment in Tunnel Crossing Section

施工裂縫對隧道穿越段堤防滲流特性的影響

吳健(JIAN WU) ； 甘磊(LEI GAN) ； 張丹(DAN ZHANG)

《台灣水利》 69卷2期 (2021/06) Pp. 16-23

https://doi.org/10.6937/TWC.202106/PP_69(2).0003

摘要

After the tunnel-shield-driving machine excavated through the north levee of Yangtze River, several transverse cracks appeared in the river embankment, and the accumulative settlement of the embankment was massive. This paper investigates the influence of cracks in the embankment construction of different depths on the seepage stability of the Yangtze River embankment. Based on the three-dimensional saturated - unsaturated seepage finite element method, the three-dimensional finite element seepage analysis model of the embankment in the tunnel crossing section was established. The seepage behavior of the embankment under different crack depths within the highest water level in history is calculated. The results show that the deep mixing pile reduces the water head obviously. The through cracks have great influence on the seepage field of the stratum around the cracks. When the crack depth is less than 8.5 m, the maximum seepage gradient of dam foundation and dam body is 0.181 and 0.206 respectively, which is less than the allowable seepage gradient of corresponding soil layer, indicating the seepage stability of the embankment can meet the requirements.

關鍵字

crossing section ； river embankment ； seepage ； finite element method ； stability

並列摘要

某長江隧道盾構機穿越江北大堤，堤身出現施工貫穿式裂縫，且累計沉降較大。本文考慮不同深度堤身施工貫穿式裂縫對長江大堤堤身滲流穩定性的影響，採用三維飽和－非飽和滲流有限元法，建立了隧道穿越段大堤的三維有限元滲流分析模型，計算分析了歷史最高水位條件下不同裂縫深度下堤防的滲流性態。計算結果表明：深層攪拌樁消減水頭的作用明顯；貫穿式裂縫對裂縫周圍地層的滲流場影響較大，但當裂縫深度小於8.5 m，堤身與堤基的最大滲透坡降分別為0.206和0.181，均小於相應材料的允許滲透坡降值，大堤的整體滲流穩定能滿足要求。

並列關鍵字

穿越段 ； 堤防 ； 滲流 ； 有限元法 ； 穩定