鋼管排樁工法應用在土石流及崩塌地防治之實務探討－以火炎山崩塌地為例

The Practical Application of the Steel Pipe-Wall Method to Control Debris Flow and Landslides-A Case Study of Houyenshan Landslides

許聖富(Sheng-Fu Sheu) ； 施志鴻(Chih-Hung Shih)

《中華水土保持學報》 46卷3期 (2015/09) Pp. 189-196

https://doi.org/10.29417/JCSWC.201509_46(3).0007

摘要

火炎山屬更新世頭嵙山層，由礫岩、間夾薄層泥質粉砂岩組成，豪雨時容易發生山崩、岩屑滑移及土石流，經核定劃設為「自然保留區」。從衛星圖像可看見大量的下移土石（主要由3號坑溝產生），已在大安溪北岸堆積成半圓形的聯合沖積扇（初估土石量超過57.6萬m^3），影響到大安溪的流況，也將影響北側支流-景山溪之匯流。目前發現1號坑溝的崩移土石已堆積至140縣道之東隧道口，不久將危及人車安全。採用鋼管排樁工法進行整治應是可行的選項，一旦解決了土石崩移的料源，後續的土石流將可避免發生。本文提出鋼管排樁之初步力學分析及設計流程初步建議，並針對施工實務，如鋼樁出露部份之防銹處理、套管驅動設備選擇、成本分析方式等相關事項提出初步探討。

關鍵字

土石流 ； 崩塌地 ； 鋼管排樁工法 ； 拱壁效應

並列摘要

The geology of Houyenshan, Miaoli County, is Pleistocene Toukoshan formation, and major gravel beds with thin layers of muddy sandstone. Landslides, detritus slides and debris flows are easily induced by heavy rainfall. It has been officially declared a natural conservation area. From the satellite image, we can see a mass of united alluvial fan on the north bank of the Da-an river impacting its water flow. Meanwhile, the gravel congeries mainly induced by No.1 gully are reaching the east portal of the tunnel along No. 140 county road. However, using the steel pipe-wall method to control the landslide and debris flow can be a good solution. This will prevent debris flows from first occurring. This paper proposes the basic analysis and design steps of a steel pipe wall. Meanwhile, some practical considerations for construction, such as the antirust arrangement of the steel pipe emersion, determination of the casing driver, cost analysis of a single steel pipe etc., are explored.

並列關鍵字

Debris flow ； Landslides ； Steel pipe-wall method ； Arching effect