2984

2838

كارشناسي ارشد

خاك و پي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده عمران

1384

يازده، 208، [II]ص.: مصور، جدول، شكل، نمودار

محمود وفائيان

بهروز كوشا

كاظم فخاريان، محمدعلي روشن ضمير

1395/12/14

كتابنامه

عمران

مهندسي عمران

ID2838

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Abstract Reinforced soil technology has been extensively used during the last decades in the construction of embankments and retaining walls A large variety of reinforcing materialsemerged and have been developed for construction purposes including metal strips steelbars geosynthetics etc Full scale experiments centrifugal and reduced scale laboratorymodel studies and field studies with the proper instrumentation of actual reinforced soil slopehave been performed to provide a rational basis for design methods of reinforcing system The similitude requirements between the reduced scalemodel and the actual prototype were foundto be difficult to formulate and practically impossible to verify Therefore the results of the laboratory model study cannot be extrapolated to provide a data base for empiricalrelationships between design parameters and system performance of actual structures However these reduced scalemodels provided a very efficient rapid and economical research tool to investigate the failure mechanisms of the reinforced soil slopes In addition with moreadequate instrumentation such models could be used in a parametrics study to evaluateavailable design approaches Some laboratory experiments were performed to observe the behavior particularly the failure conditions of steeped reinforced sandy soil slopes in small scale laboratory model under the plane strain conditions Reinforcements were made by a non woven low strength cotton papers and the loading on the soil surface was done by step wised increments of deadweights By this small model the effect of tensile strengthof reinforcement elementsand theirvertical spacing the effect of promoting different parts of the embankment on the stability ofthe embankment are among the subjects which have been studied A computational programhas also been compiled in Matlab in order to check the analytical interpretations of the results The effect of the external loading and the tensile strength of reinforcement elementshave beenadded to the well known formulae of Fellenius and Bishop by which the stability and therelevant amounts of safety factor was analyzed Based on the present study the following remarks could be concluded Failure conditions i e the failure surface and the maximum tolerable load obtained from the tests show verywell compatibility between the test results and the logical expectable behavior The resultsindicated that the cross section of the failure surface is quite and close to a circular arc in thecasescorresponding to the external loads for relatively strong reinforcement while almost astraight line for the weak reinforcement and a logarithmic spiral for the failures related to theself weight of soil Promoting the reinforcement layers or increasing the number of reinforcinglayers promoting the reinforcements in the middle height of the slope increasing the distanceof loading from the edge all are on the side of increasing the amounts of tolerable externalloads The effect of side wall friction can be evaluated almost correctly for considering instability computations Simplified Bishop s limit equilibrium formula is the most reliableequation for the analyses regarding the failure conditions and factor of safety Themodification of for considering the effect of tensile strengthof reinforcement and the side wallfriction in model tests results in excellent compatible and acceptableresults It is very reliableto accept that the peak friction angle of soil is mobilized during the failure rather than the c it Presidual c 3 b i

محمود وفائيان

بهروز كوشا

كاظم فخاريان، محمدعلي روشن ضمير