Study of regional monsoonal effects on landslide hazard zonation in Cameron Highlands, Malaysia   总被引：1，自引：1，他引：0  

Abd Nasir Matori  Abdul Basith  Indra Sati Hamonangan Harahap 《Arabian Journal of Geosciences》2011,5(5):1069-1084

In general, landslides in Malaysia mostly occurred during northeast and southwest periods, two monsoonal systems that bring heavy rain. As the consequence, most landslide occurrences were induced by rainfall. This paper reports the effect of monsoonal-related geospatial data in landslide hazard modeling in Cameron Highlands, Malaysia, using Geographic Information System (GIS). Land surface temperature (LST) data was selected as the monsoonal rainfall footprints on the land surface. Four LST maps were derived from Landsat 7 thermal band acquired at peaks of dry and rainy seasons in 2001. The landslide factors chosen from topography map were slope, slope aspect, curvature, elevation, land use, proximity to road, and river/lake; while from geology map were lithology and proximity to lineament. Landslide characteristics were extracted by crossing between the landslide sites of Cameron Highlands and landslide factors. Using which, the weighting system was derived. Each landslide factors were divided into five subcategories. The highest weight values were assigned to those having the highest number of landslide occurrences. Weighted overlay was used as GIS operator to generate landslide hazard maps. GIS analysis was performed in two modes: (1) static mode, using all factors except LST data; (2) dynamic mode, using all factors including multi-temporal LST data. The effect of addition of LST maps was evaluated. The final landslide hazard maps were divided into five categories: very high risk, high risk, moderate, low risk, and very low risk. From verification process using landslide map, the landslide model can predict back about 13–16% very high risk sites and 70–93% of very high risk and high risk combined together. It was observed however that inclusion of LST maps does not necessarily increase the accuracy of the landslide model to predict landslide sites.  相似文献   

Experimental evaluation of force analogy method (FAM) by element type     

Toloue  Iraj  Liew  Mohd Shahir  Harahap  Indra Sati Hamonangan  Lee  Hsiu Eik 《地震工程与工程振动(英文版)》2020,19(1):137-147

The force analogy method(FAM) is considered as one of the most time-saving and cost-efficient methods for analyzing frames. Through a set of assumptions and restoring forces, FAM analyzes nonlinear frames responses through Hooke's law. This study evaluates the effect of element type on FAM through numerical and experimental tests. The conventional Euler Bernoulli(EB) element is replaced by the Timoshenko(TS) beam-column element and the results are interpreted and compared with experimental findings. Three experimental tests were conducted for benchmarking and comparison purposes via 2 D aluminum frames. The results indicated that during the analysis, when the frame response is in the linear region, there is no difference between the element types in the response of the frames. When the frame entered the plastic region, the frames which were analyzed by the TS element revealed closer responses to the experimental outcomes. The gap between the results of the frame which was analyzed by EB and TS enlarged especially when the frame experienced a sharp or huge rotation of more than 0.2 rad. The final recorded deformations based on the TS element revealed an accuracy between 98.05% to 98.65%, while the EB element showed 14.66% to 45.14% for rotations of more than 0.2 rad at plastic hinge locations(PHLs).  相似文献   

Mechanical response of saturated and unsaturated gravels of different sizes in drained triaxial testing     

Alhani  Israa Jamal  Noor  Mohd Jamaludin bin Md  Al-Bared  Mohammed Ali Mohammed  Harahap  Indra Sati Hamonangan  Albadri  Wael Mahmood 《Acta Geotechnica》2020,15(11):3075-3093

Acta Geotechnica - During the construction of pavements, gravelly soil is used as the main material in the base and sub-base layers. Predicting the deformation behaviour of gravelly soil has been...  相似文献   

Experimental studies of the flow-front and drag forces exerted by subaqueous mudflow on inclined base     

Zainul Faizien Haza  Indra Sati Hamonangan Harahap  Lema Mosissa Dakssa 《Natural Hazards》2013,68(2):587-611

Submarine slides are one of the most complex geotechnical problems causing serious damages to the seabed environment. Damages may lead to imminent destruction of offshore facilities such as platform and subsea pipeline. Mud sediment was the most susceptible of subsea material involved in the event. The completeness of field investigation is very limited; therefore, laboratory experiment is implemented in view of modeling the dynamics movement at the time of submarine slides occurs. The current experiment was conducted by generating the mudflow in water ambient over an inclined base to observe the flow-front structures of the mudflow. As facility to investigate the drag force exerted by mudflow, additional pipe model was positioned at certain flow distance. Mud models were prepared from mixtures of 10–35 % by weight of kaolin and water. Mudflow observations were limited to 3.5-m run-out distance with an exemption for 35 % KCC since this percentage stopped flow at 2.3-m flow distance. The role analysis of destructive flow was developed by the determination of drag force coefficient exerted by mudflow incorporating the Reynolds number. Velocity analysis indicates that all flows were defined as initial flow since they have only one phase of slumping phase. With respect to head-flow height and densimetric Froude number, the general form of velocity propagation formula provided the satisfactorily results in tracing mudflow velocity observation of laboratory experiment. Furthermore, the higher percentage of KCC exerted the higher drag force than the lower one.  相似文献