預鑄塊疊砌式擋土設施力學行為之探討

台灣在地狹人稠、地質條件脆弱之條件下，加上地震發生頻率高、全球暖化與極端氣候變遷等因素，造成近年來短時強降雨引發野溪與邊坡災害不斷。為了維持邊坡開挖與回填時之安全性，工程應用上常以擋土設施來穩定邊坡或溪岸。隨著時代環境的轉變，過去忽略了生態保育，擋土工程多以安全為主要考量，導致整體生態環境、生物棲息地及環境永續發展造成衝擊。故近年來為了能在兼顧生態、美觀與安全的前提下，提倡公共工程生態工法之觀念，運用多孔隙、塊體堆疊，並結合就地取材、善用土石資源、混凝土減量，以達到坡面穩定為目標。本研究運用不同高度、不同斜率之預鑄塊疊砌方式探討擋土設施力學行為，研究結果顯示，隨擋土設施坡度越緩及預鑄塊疊砌層數越高，抗傾倒及抗滑動安全係數明顯提高，特別是傾斜度越緩，安全性與穩定性增加。預鑄塊體疊砌數量增加，基礎容許承載力安全係數越低。本研究分析中垂直應力增加，雖安全係數降低，惟仍均符合水土保持設計規範安全係數大於3.0之範圍。另推估分析設計護岸或擋土構造物高度仍以不超過7m為宜，此與水土保持技術規範相符。

關鍵字

擋土設施；邊坡穩定性；安全係數；技術規範

並列摘要

In Taiwan, when earthquakes continue to occur in the region and the dense geological conditions are fragile, coupled with climate change factors such as climate change, frequent changes, and changes in climate conditions, severe weather such as sudden short-term warming and climate change occurs. In order to maintain the safety of slope excavation and backfilling, earth retaining facilities are often used to stabilize the slope in engineering applications. With the changing environment of the times, and the neglect of ecological conservation, the main consideration of early earth-retaining projects was safety, which led to an impact on the overall ecological environment, biological habitats and sustainable development of the environment. Therefore, in recent years, in order to promote the concept of ecological construction method of public works under the premise of taking into account ecology, beauty and safety, the use of porous, block stacking, combined with local materials, good use of soil and stone resources, and concrete reduction, in order to achieve slope surface stability is the goal. In this study, the method of stacking the blocks with different heights and slopes used to investigate the mechanical behavior of retaining facilities. The results show that: as the slope of the retaining facilities is gentler, the higher the numbers of stacked layers of pilaster blocks, the anti-dumping and anti-sliding safety factors are significantly improved. As the number of stacked blocks increases, and the lower the safety factor of the foundation's allowable bearing capacity. When the vertical stress increases, although the safety factor decreases, it still conforms to the design specification for water and soil conservation where the safety factor is greater than 3.0. In addition, it is estimated that the height of the revetment or soil retaining structure should not exceed 7m in the analysis and design, which is in line with the technical specifications for soil and water conservation.