Grunto, armuoto geotinklais, kerpamojo stiprio tyrimai

Abstract

Straipsnyje apžvelgtos grunto kerpamojo stiprio savybės, kai gruntui armuoti yra naudojami geotinklai. Pastaruoju metu šis metodas Lietuvoje yra plačiai taikomas statybų srityje, tiesiant kelius ir geležinkelius. Triašio slėgio bandymuose tirti vieni iš dažniausiai grunto armavime naudojamų lanksčių ir standžių geotinklų, kurių stipris tempiant išilgai ir skersai ≥40 kN/m. Gauti pikinių ir liekamųjų kerpamojo stiprio rezultatai palyginti su nearmuoto grunto, atliktas palyginimas tarp standžiais ir lanksčiais geotinklais armuotų bandinių. Nustatyta, kad geotinklų naudojimas armuojant grunto kompozitines konstrukcijas pagerina armuotų konstrukcijų savybes, palyginti su nearmuotomis.

This paper presents the results of a static triaxial test on soil samples reinforced with geogrid, conducted with the aim to characterize the shear strength of reinforced soil composite. To reach the aim it was chosen to provide triaxial tests without geogrid reinforcement and to compare later obtained results with soil samples reinforced with geogrid. Two types of flexible geogrid and one type of rigid geogrid were selected with ultimate tensile strength ≥40 kN/m. Laboratory testing programs were performed with a static triaxial test device, where sample diameter was 100 mm and height was 200 mm. The samples were made with initial water content of 6.00% and average density varying from 1.67 to 1.73 g/cm3 (according to different geogrid reinforcement type). The reinforcement layer was placed directly in the middle of the samples and all triaxial tests were conducted according to isotropic, unsaturated, consolidated and drained conditions with three confining cell pressures: 100, 200 and 300 kPa. During the loading stage, there was used a 0.950%/min vertical strain ramp, until maximum deformation of 15.0% was reached. The effect of different geogrid reinforcement on shearing strength results was analyzed, mainly peak and residual shearing strength. The tests results revealed that the shearing strength increases if soil sample is reinforced with geogrid. Using flexible geogrids, the maximum peak shearing strength was reached at higher vertical strains when compared with a rigid geogrid. In general, the improvement of shearing strength is obtained with soil samples reinforced with flexible and rigid geogrids compared to samples without reinforcement. In this study, flexible and rigid geogrids used for experimental testing are equivalent products, which can be successfully applied for Lithuanian roads and railways structures.