A STUDY ON SOIL. NAILING WITH RESPECT TO OPEN EXCAVATIONS AND SLOPES

Abstract

Construction activities are the essential part of any Country's development. To match the need of development with the constructs of meager space available for development, new construction methodology is to be evolved. Soil Nailing is one of the emerging technologies which can help Civil engineers for underground construction, slope stability, vertical cuts etc. The literature available on this technique reveals most of findings on experimental and empirical studies. In the present study, attempt has been made to develop design charts for construction of open excavations, vertical cuts, trenches etc. In the present study vertical as well as inclined cuts have been analyzed by assuming log-spiral ruptures surface. The present study is slightly different from the approach adopted by Gassier who has assumed pull out test as the ultimate method of determination of tensile force in nail material. In the present study tensile force in the nail material has been determined with the help of strength parameter of nail material. All the possible variables. e.g. nail angle, nail length, nails structural geometry, nail's spacing, (horizontal & vertical ), method of nail installation, type of loading, nail materials etc have been incorporated in the study. It has been found that the optimum nail angle (Q) with the perpendicular to the face of excavation lies between 0 to 10° The optimum length is between 0.6 to 0.8 h, h being the height of wall. Grouted nails are found to exhibit more factor of safety as compared to driven nails. The plastic modulus of the nails material also plays an important role; higher the plastic modulus, more the factor of safety..