Mechanism Of Lateral Resistance Of Rock-socketed Piles In Weak Rock Area And Its Indoor Model Test

With the development of traffic construction in the western mountainous areas,the demand for large-scale bridge construction is increasing day by day.Rock-socketed piles have been widely used in bridge projects due to their high bearing capacity,small settlement,and the fact that the pile ends are not affected by environmental factors.However,due to the high bearing capacity of the rock-socketed piles,it is difficult to apply the load to the failure load in the field test,and the construction process is complicated,and there is still no clear understanding of the load transfer mechanism of the rock-socketed piles.As a result,it is difficult to excavate the bearing potential of the rock-socketed piles in the project,which not only increases the difficulty of construction,but also leads to waste of economic costs.Many studies at home and abroad have proved that the bearing capacity of rock-socketed piles is mainly provided by the lateral resistance of the rock-socketed sections.With consideration of the weak rock conditions of rock-socketed piles,taking the dilatancy of the interface into account,the constant normal stiffness conditions(CNS)were applied to simulate the lateral constraints provided by weak rock,and laboratory model tests were conducted to inquire the mobilization of the side resistance.Based on the results,the factors affecting the side resistance of the pile rock were analyzed.The formula for calculating the lateral resistance considering the compression of the asperity was discussed.Based on this,the calculation method of the pile load transfer was studied.First of all,collect relevant literature and literature about rock-socketed piles at home and abroad to understand the theoretical mechanism of interf acial shear at home and abroad,and deeply understand the relevant foreign indoor model test programs.Designing test equipment and test programs to reasonably design the roughness of the specimen,simplifying the rough body of the pile-rock contact surface into a regular triangular serration,and making sandstone and concrete specimens according to different half wavelengths.For the shear test under normal normal stiffness,the relationship between shear load,shear displacement,normal load and normal displacement is obtained.Secondly,the test results show that the normal dilatancy angle of the sawtooth in weak rock shows a nonlinear decrease with the increase of the shear displacement,and the shear strength of the interface and the normal constraint s tiffness,the half wavelength of the rough body and the shear displacement Such as closely related;At the same time,considering the impact of the elastic compression of the surface of the weak rock on the interface dilatancy angle,using the power functi on to fit the empirical relationship of weak rock shear strength.Comparing the experimental results with the results of the existing theoretical models,it is shown that the existing model ignores the non-linear variation of the dilatancy angle at the rock-pile interface and will overestimate the side resistance of the rock-socketed pile.Finally,the load transfer function established in this paper is compared with the field data of a test pile to verify the applicability of the load transfer function.Ba sed on this article,subsequent studies can consider the impact of various factors on nonlinear compression.