Deep-layer flat plate load in-situ test method for ultra-thick-layer backfill soil

Abstract

The invention discloses a deep-layer flat plate load in-situ test method for ultra-thick-layer backfill soil. According to the method, an in-well expanded diameter is formed through an artificial deepwell and used for placing load test equipment, a reinforced concrete ring beam is designed on the top surface of a well diameter expanded part, and the ring beam gravity and the friction force between the side wall of a protection wall at the upper part of the ring beam and a soil body are used as a counter-force device for a deep-layer flat plate load in-situ test, so that the counter-force in the deep-layer flat plate load in-situ test is clear in stress and stable in action with a loading device; and a space with the diameter of 1 m is formed below the expanded part by 80 cm, and used forplacing a pressure bearing plate, a jack, a displacement meter, a force transfer column and the like, moreover, a soil body semi-infinite space is formed, the stress state inside the soil body can beshown, meanwhile, the influence of lithology and loading depth is avoided, elastic deformation and bending deformation of the force transfer column in the loading process are effectively controlled, and meanwhile, multiple test monitoring methods are adopted, so that the precision and the accuracy of test data are improved.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering, in particular to an in-situ test method for deep plate loads used for super-thick layer backfill soil. Background technique [0002] In the development and application of geotechnical engineering, in the design and testing of foundations for elevation, super-elevation structures, heavy industrial plants, bridges, etc., the standard value of foundation bearing capacity provided by the load test or the pile tip soil should be used. The standard value of bearing capacity, due to the deep burial of the foundation and the large load, has strict requirements on the foundation, and the conventional load test method cannot reflect the authenticity of the mechanical properties of the deep foundation soil, so other in-situ test methods are commonly used: such as static penetration testing and dynamic penetration testing , side pressure test, standard penetration test and other methods give empirical...

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Problems solved by technology

[0004] The in-situ test method of deep plate load commonly used at present is greatly affected by the depth and stability of lithology and soil layers, and at the same time, the deformation and bending of the dowel bar and the displacement and deformation of the reaction force system during the loading process affect the accuracy of the test data. Accuracy, the general test depth is up to about 20m. In the area of ​​super-thick backfill soil, the stability of the backfill soil is poor, the degree of soil consolidation is poor (generally under-consolidated soil), the soil structure is loose, and the ground anchor provides The reaction force is not enough to meet the requirements of the test and the spiral plate load test is difficult to reach the required depth of the test. At the same time, the deep plate load in-situ test method is difficult to realize when the test depth is large, and the conventional manual digging hole (vertical wall) and the force transmission column The increase of the slenderness ratio will produce a large deformation, seriously affecting the accuracy of the test

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