Abstract
Soil-nails are used to stabilise a soil mass by exploiting the resistance generated by the skin friction between the ground and grout and the tensile stiffness of the reinforcing material. A load–displacement curve is obtained from in situ pullout load tests performed by considering the elastic shear modulus and ultimate skin friction capacity between the soil and grout. This study determines the shear behaviour between the soils and grout analytically, especially the soil-dilation effect during shearing that is one of the main factors affecting the ultimate skin friction, even though this estimation is rather cumbersome. Many studies assume a full bond between the grout and the steel reinforcing bar, thus neglecting their relative displacement. In this study, the net load–displacement between the ground and grout is obtained by subtracting the nail elongation from the load–displacement of the pullout tests when estimating the shear displacement. Numerous field pullout tests are performed in this study under various ground conditions and through various construction methods. The dilatancy angles are estimated dependent on the soil type by comparing the net load–displacement curve obtained in the field with that obtained theoretically.
Highlights
Soil-nailing is a technique used to improve the stability of earth structures by inserting a reinforcing material and grout into the ground (NHI, 2015)
The net load–displacement curves are estimated according to ground conditions as well as construction methods
The theoretical results obtained are compared with field test data; the back-calculated dilatancy angle is obtained to be used as an initial estimate when obtaining the ultimate skin friction by matching two curves. (b) Three different sites and two different construction methods were considered in the investigation
Summary
Soil-nailing is a technique used to improve the stability of earth structures by inserting a reinforcing material and grout into the ground (NHI, 2015) It is a passive method because resistance occurs only during ground movement. The shear displacement between the ground and grout in loose soil predominantly occurs when the ultimate skin friction is far smaller than the tensile strength of the reinforcing. It is possible to estimate the net load–displacement between the ground and grout by subtracting the nail elongation when estimating the shear displacement from the load–displacement curve obtained from the pullout tests. A number of field pullout tests were performed in this study under various ground conditions and construction methods, and the net load–displacement curves obtained in the field are compared with those obtained from the theoretical solution. The resisting contribution of the skin friction component as compared to that of the steel bar can be derived
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the Institution of Civil Engineers - Geotechnical Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
