بررسي آزمايشگاهي ظرفيت باربري ماسه مسلح به ژئوگريد با آرايش غير يكنواخت

چكيده انگليسي :

Experimental Study on Bearing Capacity of a Sandy Soil Reinforced with Nonuniform Distributed Geogrids Mohsen Karimian Mhsn karimian@yahoo com Date of Submission March 8 2011 Department Collage of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mohammad Ali Rowshan Zamir Mohamali@ cc iut ac ir Abstract Soils are mostly weak in tensile strength and need to be strengthened by adding tensile elements In the past decades several methods have been proposed to improve the soil mechanical properties About the important of soil can be express that the soil reinforcements also technically and economically most cases is advantage over other methods Structural point of view due to the armed soil flexibility and high damping which has good performance in front of earthquakes at their leaves instead of economically because of the ease of implementation execution and low cost of the necessary materials soil and Armed visitors using this method can be adhered to the first preferences Another important direction of the soil reinforced in which this method of granular soil and cohesive soil as a material involved with reinforced elements can be used One of the proposed methods is the soil reinforcement which was introduced by Henri Vidal in 1960 Reinforced elements as strips grids wires fabrics felt etc from Steel aluminum plastics polymeric materials have been used for this purpose Geogrids which entailed a group of geosynthetic products are used widely as soil reinforcements to enhnce the soil bearing capacity and reduce its settlement due to footing loads Extensive research has been done on the reinforced soil with geogrids which mostly involved with the same length of reinforcements in all layers as a uniform block with depth However regarding the predicted sliding zones in the supporting soil of footings it appears that the longitudinal arrangement of reinforcement layers with depth could affect on the footing bearing capacity The main purpose of this research study was to investigate the likely effects of variations in geogrids arrangements placed in a sandy bed on the footing bearing capacity In order to achieve this purpose using gegrids reinforcement layers the bearing capacity of footing models was evaluated for uniform and non uniform reinforcement arrangements Three different reinforcement blocks were selected for considering nonuniform arrangements the first group included the arrangements in which the length of geogrid layers increased with depth trapezoidal state the second included the arrangements in which the length of geogrid layers decreased with depth inverse trapezoidal state and the last group included variable increase and decrease of geogrids length with depth variable state The influences of footing shape including circular square and strip forms on the bearing capacity were also considered In addition the effects of the soil bed density on the footing performance were investigated The footings load tests indicated that in all forms of footings as well as all considered densities the greatest bearing capacities were occurred in inverse trapezoidal reinforcing arrangements while the least bearing capacities were involved with trapezoidal arrangements The range of bearing capacity improvement ratio obtained from the footing load tests conducted on the geogrids reinforced sandy soil varied from 1 5 to 6 depending the soil density the footing shape and the reinforcing arrangement Keywords bearing capacity reinforced soil nonuniform reinforcement uniform reinforcement

كريميان، محسن

بررسي آزمايشگاهي ظرفيت باربري ماسه مسلح به ژئوگريد با آرايش غير يكنواخت

خاك مسلح , تسليح غير يكنواخت , آرايش ذوزنقه اي , آرايش متغير