Rock side friction test device and method with controllable confining pressure

Abstract

The invention discloses a confining pressure-controllable testing apparatus and testing method for the lateral friction of rock, belonging to the field of technology for embedding piles in rock in rock mass mechanics. The apparatus is such structured that a lower cover plate, a pressure chamber and an upper cover plate are successively connected from top to bottom to form an external structure; a base, a backing ring, a rock sample and a guide pipe are successively connected from bottom to top to form an internal structure, and a latex film is used to nest the above-mentioned internal members into an integral body; a through rock sample circular hole is longitudinally arranged at the center of the rock sample, threaded rods of a same length are arranged in the rock sample circular hole, gaps are left between the threaded rods and the inner wall of the rock sample circular hole and cement mortar with high fluidity is poured into the gaps; and a guide rod passes through the guide pipe and connected with the threaded rods in an up-and-down manner. The apparatus can simulate the failure characteristics of rock-socketed piles and a rock interface and hydraulic pressure action in a pressure chamber is employed to simulate confining pressure conditions of the piles in an actual rock stratum, so the law that axial force changes with displacement of the model piles is obtained and the lateral friction of rock is calculated; and the testing apparatus and testing method have unified standards, can be industrially replicated a plurality of times and are applicable to testing of lateral friction of a variety of rock masses.

Description

technical field [0001] The invention relates to rock mechanics rock-socketed pile technology, in particular to a rock side friction resistance testing device with controllable confining pressure and a method thereof. Background technique [0002] Due to its high bearing capacity, rock-socketed piles are widely used in pile foundation projects of factories, bridges, docks and high-rise buildings. At present, it is agreed at home and abroad that the rock side friction of the rock-socketed part contributes a lot to the bearing capacity of the pile. There are differences in rock side friction at different depths. This is due to the fact that rocks have different in-situ stresses at different depths. Therefore, it is necessary to accurately obtain the rock side friction in a specified formation environment, which is reflected in the model test. The confining pressure conforming to the actual in-situ stress is applied to the rock sample. The previous method is to obtain the side...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the shortcomings of high cost and large variable factors in field test piles, avoid abnormal failure surfaces caused by fixtures and human factors, and provide a rock side friction resistance test device and method with controllable confining pressure. The above errors can be avoided, and the lateral frictional resistance of the rock under the specified confining pressure can be accurately obtained

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