Introduction to Remediation Methods
The Anti-Slide Pile Method is one of the common measures in the remediation of large-scale collapses and sliding slopes. Reinforced concrete piles are driven or drilled and grouted into stable bedrock to resist the thrust of the sliding soil mass and stabilize the slope surface.
The Subsurface Drainage Method guides groundwater out through drainage tunnels, collection wells, and drainage pipes, reducing the pore water pressure in the slope body and improving slope stability. It is often used in conjunction with anti-slide piles or retaining walls.
The Reinforced Soil Structure combines soil with reinforcement materials (such as geogrids) to enhance the shear strength and bearing capacity of the soil mass, which is suitable for shallow slope remediation.
The Anchored Retaining Wall combines a retaining structure with an anchor system to transfer earth pressure to the stable rock and soil layers, which is suitable for medium to deep sliding slopes.
Remediation Method Cases
The large-scale collapse area "Taichung City - Heping District - Daguang D016" is located in Daguang Village, Heping District, Taichung City, covering an area of approximately 59.74 hectares and protecting about 60 households. To understand the changes and risks of the collapse area, basic data collection, surface geology and current situation investigation, airborne LiDAR, geological drilling, geophysical exploration, and monitoring instrument installation were conducted. Survey results indicate that deep-seated sliding may occur at the interface between the colluvium and the bedrock, and groundwater levels rise during rainfall. Phenomena such as cracks, depressions, colluvium slumping, and surface erosion were also observed on the slope. The comprehensive assessment concludes that the current situation is mainly shallow collapse caused by surface erosion. Therefore, the remediation plan focuses on surface and subsurface drainage and slope surface stabilization, supplemented by continuous monitoring to track changes in slope stability.
Source：https://swcdis.nchu.edu.tw/AllDataPos/JournalPos/%E7%B7%A8%E8%99%9F59/%E7%AC%AC2%E6%9C%9F/%E5%A4%A7%E8%A6%8F%E6%A8%A1%E5%B4%A9%E5%A1%8C%E6%BD%9B%E5%8B%A2%E5%8D%80%E8%AA%BF%E6%9F%A5%E7%9B%A3%E6%B8%AC%E8%88%87%E6%95%B4%E9%AB%94%E6%B2%BB%E7%90%86%E8%A6%8F%E5%8A%83%E7%A0%94%E6%93%AC-%E4%BB%A5%E8%87%BA%E4%B8%AD%E5%B8%82-%E5%92%8C%E5%B9%B3%E5%8D%80-%E9%81%94%E8%A7%80D016%E7%82%BA%E4%BE%8B-20230718.pdfDue to frequent extreme rainfall events, the geology along the Tengzhi Access Road is unstable, leading to multiple slope collapses and roadbed loss, especially a severe landslide after Typhoon Haitang in 94 (2005). To address this issue, the Pingtung Forest District Office of the Forestry and Nature Conservation Agency implemented phased remediation projects, combining geological surveys and continuous monitoring to evaluate and adopt various composite construction methods such as anti-slide piles, prestressed ground anchors, and horizontal drainage pipes to stabilize the slope.
Source：https://kmweb.moa.gov.tw/knowledgebase.php?func=1&type=13213&id=384409The collapse area in Erwanping and Pingzhena is massive. The Chiayi Forest District Office has carried out phased remediation since 101 (2012), including engineering measures such as slope surface drainage, gully rectification, cut-and-fill slope grading, and new retaining facilities, with the aim of increasing the slope's anti-slide strength and mitigating headward erosion. Furthermore, multiple sediment control facilities and revetment structures were installed at the toe of the slope along the Alishan Stream to stabilize the toe of the collapsing slope and prevent continuous scouring.
Source：https://kmweb.moa.gov.tw/redirect_files.php?theme=knowledgebase&id=566039
