Executive Summary : | Rainfall-induced slope failures occur in response to climatic changes in many parts of
the world. Climatic changes result in dynamic flux boundary conditions across slope
surface, such as infiltration and evaporation. In addition, trees, shrubs and grass
generate another dynamic process of transpiration across slope surface. As a result,
stability of a slope as quantified by factor of safety is not constant over time, but varies in
accordance with variation in flux boundary conditions. In other words, slopes are
infrastructures whose stability is highly dependent on environment and whose failure has
detrimental impacts on environment and public safety.
Effect of climatic changes on slopes can be assessed using real-time monitoring. Several
geotechnical instruments such as piezometer, tensiometer, inclinometer and devices for
measuring changes in local climate such as rainfall gauge and weather station are to be
installed within the chosen slope area. The data from these instruments are captured
automatically using a data acquisition system and the data are transported to a secured
website in real time using a General Packet Radio Service (GPRS). Although the cost of
installing the real-time monitoring system can be costly, the system does provide
valuable information for authorities to determine the risks involved and to make an
informed decision with respect to critical slopes near public facilities. In other words,
real-time monitoring of critical slopes help maintain environmental sustainability of the
local areas. The main objectives of the proposed project are as follows:
(1) To find out the scope of activities of the potential landslide section, exploring deep deformation activities of landslides and the exact location of the sliding surfaces and sliding rate, etc. through field monitoring. These data should be provided for engineering design purpose;
(2) Development of the failure mechanism of the soil slope and delineate the effect of seepage forces during rainfall infiltration on the stability of the slope.
(3) Investigation of the nail forces with time at various stages of seismic loads and the load transfer mechanism of nails under seismic load condition.
(4) Appropriate remedial measures to be undertaken considering the assessment results from the real time-monitoring observations and also their monitoring though the same field instrumentation to evaluate their usefulness in slope stability improvement.
(5) When the project will be completed, through the long-term observation, one should further analyze and evaluate the stability of landslide and the effectiveness of the project.
(6) Development of some guidelines for predicting the failure pattern of soil slope and distribution of pore water pressure for various rainfall patterns. |