Abstract: Urban advances and the growing need for developing infrastructures has increased the importance of deep excavations. In this study, after the introducing probability analysis as an important issue, an attempt has been made to apply it for the deep excavation project of Bangkok’s Metro as a case study. For this, the numerical probability model has been developed based on the Finite Difference Method and Monte Carlo sampling approach. The results indicate that disregarding the issue of probability in this project will result in an inappropriate design of the retaining structure. Therefore, probabilistic redesign of the support is proposed and carried out as one of the applications of probability analysis. A 50% reduction in the flexural strength of the structure increases the failure probability just by 8% in the allowable range and helps improve economic conditions, while maintaining mechanical efficiency. With regard to the lack of efficient design in most deep excavations, by considering geometrical and geotechnical variability, an attempt was made to develop an optimum practical design standard for deep excavations based on failure probability. On this basis, a practical relationship is presented for estimating the maximum allowable horizontal displacement, which can help improve design conditions without developing the probability analysis.
Abstract: This paper represents the basic idea and mechanisms associated with the durability of geomembranes and discusses the factors influencing the service life and temperature of geomembrane liners. Geomembrane durability is stated as field performance and laboratory test outcomes under various conditions. Due to the high demand of geomembranes as landfill barriers and their crucial role in sensitive projects, sufficient service life of geomembranes is very important, therefore in this paper, the durability, the effect of temperature on geomembrane and the role of this type of reinforcement in different types of soil will be discussed. Also, the role of geomembrane in the earthquake will be considered in the last part of the paper.
Abstract: By enhancing the applicatıon of grounds for
establishment and due to the lack of appropriate sites, engineers
attempt to seek out a new method to reduce the weakness of soils. İn
aspect of economic situation, various ways have been used to
decrease the weak grounds. Because of the rapid development of
infrastructural facilities, spreading the construction operation is an
obligation. Furthermore, in various sites with the really bad soil
situation, engineers have considered obvious problems. One of the
most essential ways for developing the weak soils is stone column.
Obviously, the method was introduced in France in 1830 to improve
a native soil initially. Stone columns have an expanding range of
usage in different rough foundation sites all over the world to
increase the bearing capacity, to reduce the whole and differential
settlements, to enhance the rate of consolidation, to stabilize slopes
stability of embankments and to increase the liquefaction resistance
as well. A recent procedure called installing vertical nails along the
round stone columns in order to make better the performance of
considered columns is offered. Moreover, thanks to the enhancing the
nail diameter, number and embedment nail depth, the positive points
of vertical circumferential nails increases. Based on the result of this
study, load caring capacity will be develop with enhancing the length
and the power of reinforcements in vertical encasement stone column
(CESC). In this study, the main purpose is comparing two methods of
stone columns (installed a nail surrounding the stone columns and
using geogrid on clay) for enhancing the bearing capacity, decreasing
the whole and various settlements.
Abstract: This study investigated the behavior of improved soft soils through the vibro replacement technique by considering their settlements and consolidation rates and the applicability of this technique in various types of soils and settlement and bearing capacity calculations.