Comparison study on the calculated and the monitored tensile force of soil nail according to the new and old specifications
Zhang Qinxi;Wang Xiaojie;Tao Tao;College of Architecture and Civil Engineering,Beijing University of Technology;
In order to meet the needs of project construction,the Ministry of Construction in April 5,2012 formally issued "Technical specification for retaining and protection of building foundation excavations"( JGJ 120-2012). Taking a typical project as example,the tensile force is monitored by embedded vibrating wire reinforced dynamometer,and calculated according to both the new and the old standard. Comparing the values,it is found that the axial tensile force of soil nail calculated according to the new specification( JGJ 120-2012) is more suitable to the wedge nailing model than that according to the old specification( JGJ 120-99). The present soil nailing design method is more reasonable. The calculated nail axial tension force is far greater than the measured which means the safety factor is large.Reasonable selection of experience coefficient ηbis an important factor for the soil nailing design.