The Necessity of The Consideration of Permeability Modifier in Simulations of Clay Treatment Systems Incorporating PVDs and Surcharge

Three trial embankments as TS1, TS2, and TS3 that were built for the investigation of a soil treatment project in Bangkok were modeled and verified based on the reported data. To clarify the importance of integration of the hydraulic modifier function vs stress, in the verified models, the modifier functions were omitted and the FEM models were run in the absence of the function. It was shown that after the omission of the hydraulic modifier, the results were overestimated especially for the TS1 and TS2, which had smaller PVDs (prefabricated vertical drains) distance. For the TS1 embankment, the settlement increased from 0.78 m to 0.87 m in 210 days. In 365 days, the settlement increased from 1.27 m to 1.44 m. For the TS2 embankment, the settlement increased from 0.93 m to 1.67 m in 230 days. In 410 days, the settlement increased from 1.36 m to 2.27 m. For the TS3 embankment, the settlement increased from 1.15 m to 1.79 m in 230 days. In 410 days, the settlement increased from 1.52 m to 2.24 m. The inclusion of the hydraulic function that calibrates the model for every step of loading is essential in the modelling such problems. For the design phase, this function should be calculated from lab tests, preferably undisturbed samples that were bored from the site, and the resultant function be used as an inseparable part of modeling and calculations.Journal of Civil Engineering and Materials Applicatio

Using stone column as a suitable liquefaction remediation in Persian Gulf coast.

This research investigates behavior of gravel drain piles under high-level earthquake loading beneath the structures foundation. To achieve this purpose one of the waste water septic tank project in north of Persian Gulf in Hormoz Island was selected as a case study to find suitability of gravel drain pile system to reduce excess pore water pressure. According to high susceptibility of local soil layers liquefaction and its short distance of waste water tank to the sea, the mentioned project becomes one of the most important issues regarding geo-enviro nmentally hazards impact after tank structural collapsing. The drain piles were used to control excess pore water pressures beneath the foundation of mentioned project. Furthermore, different static and cyclic triaxial tests, Standard Penetration Test (SPT), the hydraulic conductivity and density tests were conducted to enhance the proper understanding of the dynamic behavior of soil layer under the foundation. According to the numerical modeling results, using these drain piles has focal effects on the excess pore water pressure rate and creates a liquefaction zone during the time of earthquake loading

Preventing landslides in times of rainfall: case study and FEM analyses

Purpose: The purpose of the paper is to present a new method of controlling through susceptible slopes in order to reduce the risk of landslides. Design/methodology/approach: Geotechnical and geological characteristics were collected and different FEM analyses were carried out in a case study of the Alasht valley in Northern Iran in order to determine susceptibility to landslides and consider appropriate countermeasures. Gravel drain piles have a real feel of reducing the pore water pressure in times of seismic loading, so they are used as a remediation method. The results clearly show their effects and an increase in safety as a result. Findings: Since the water table situation has a significant effect on stability, the present study focused on an example of using a seepage controlling system and its effect on the safety factor for different slopes in the area of Alasht, Northern Iran. Several FEM analyses were carried out on a landslide susceptible case. The results from FEM analysis of different slopes in the study area show a high susceptibility to landslides for six sites. Installing a gravel drain pile surrounded by a non-woven geotextile layer leads to an increase in the safety factor against landslides. As a result, after installing gravel drain piles in the upper parts of slopes in order to control run out and ground water rising up in times of heavy rainfall, the safety factor against landslides in both static and seismic loading improved significantly. Originality/value: The literature regarding controlling seepage in order to reduce the risk of landslides is limited. This paper collects and analyses geotechnical and geological data from the Alasht valley as an example to show the high risk of susceptibility to landslides