Three-Dimensional Numerical Investigation on the Efficiency of Subsurface Drainage for Large-Scale Landslides

Abstract

This paper presents a field monitoring study with emphasis on the design and construction of a subsurface drainage system and evaluation of its stabilization efficiency on the slope of You-Ye-Lin landslide using a three-dimensional finite element method program (Plaxis 3D) for the groundwater flow and slope stability analyses. The subsurface drainage system consists of two 4-m diameter drainage wells with multi-level horizontal drains and was installed to draw down the groundwater level and stabilize the unstable slope of the landslide. Results demonstrate that the subsurface drainage system is functional and capable of accelerating the drainage of the infiltrated rainwater during torrential rainfalls during the typhoon season. The large groundwater drawdown by the subsurface drainage system protects the slopes from further deterioration and maintains the slope stability at an acceptable and satisfactory level.

Rainfall-Induced or Lake-Water-Level-Controlled Landslide? An Example from the Steep Slopes of Lake Balaton, Hungary

“…One study found that such a dramatic change in surface-groundwater interactions was due to quick surface-water recession and delayed groundwater response [71]. Groundwater drawdown can protect the slopes from further deterioration and can maintain the slope stability at an acceptable and satisfactory level [72]. The Plaxis models do not achieve the safety factor of 1.35 required by the international geotechnical standard Eurocode7 at any water level.…”

Exploration and Sustainable Management of Groundwater Resources in Geologically Complex Terrain

“…For instance, an active landslide (You-Ye-Lin landslide) in the mountainous area of Taiwan has a long history of intermittent large downslope ground movements affected by groundwater during rainfall periods since Typhoon Morakot in 2008. In [10], to prevent the expansion and deterioration of the landslide, an effective remediation method for slope stabilization, which is to lower the groundwater level through a deep subsurface drainage system composed of two drainage wells, was proposed to investigate its feasibility and stabilization efficiency. A three-dimensional finite element method program (Plaxis 3D) was used to perform the groundwater flow and slope stability analyses.…”

Performance Evaluation of Artificial Recharge–Water Intake System Using 3D Numerical Modeling

“…In addition, MOD-FLOW has been used to analyze the groundwater flow in a ditch filled with homogeneous anisotropic soil [8], and a numerical analysis model was developed to examine the application of groundwater artificial recharge in the Yongding River basin in Beijing, China [9]. Meanwhile, an underground drainage system that can mitigate landslide damage was developed and constructed on site; the stability of landslides and slopes was reviewed using a three-dimensional finite element program (Plaxis 3D) [10].…”