Slope Stability Analysis for Remediation Project Along the Catanduanes Circumferential Road Network System
Dexter M. Toyado
This paper attempts to (1) Analyze Slope Stability, Landslide Susceptibility, and Soil Nails application, (2) Provide a numerical analyses, visual views and interpretation of Slope Stability problems and Factor of Safety, (3) Offer technical and comprehensive solutions of the identified unstable slopes confronting the road network system for remediation projects. The Landslide Susceptibility Map (LSM) along the Catanduanes Circumferential Road Network System (CCRNS) showed that Parts of Tubli-Dariao-Guiamblong Area, Hitoma Area and San Andres Area where the CCRNS is situated indicates moderate to high susceptibility to landslide. The Landslide Simulation along these areas shows that the Factor of Safety (FS) is highest in both the 30, 40 and 50 degrees slopes when the water level is just below the top layer and lowest when the water level is at the ground surface. When the water table is at the midpoint of the Top Layer, the FS in all areas has an average of 1.157, 0.972, and 0.934 in both 30, 40 and 50 degrees slopes, respectively. This safely suggests that the increment of water level or saturation of soil contribute to slope failure. It is evident that when the rainfall occurs and when it saturates the soil, a very high potential of slope failure will occur on the slopes along the CCRNS. The saturation on the soil type that is found in the province is about 50 mm per day at the average. Two consecutive days or an accumulated rainfall of 140 mm in 48 hours would result on slope failure. The simulation of the application of the Soil Nails at an appropriate intervals using 30° slope shows that Areas with Soil Reinforcement have higher Factor of Safety than Areas without Soil Reinforcement. Thus, To prevent slope failures along the CCRNS the application of Soil Reinforcements is necessary. This paper suggests a Soil Nail application and full Reforestation of the areas along the CCRNS to prevent occurrences of landslides.
Keywords: Factor of Safety, Slope Stability, Soil Nail, Landslide Susceptibility
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