Method and device for in-situ penetration test by means of water injection under drilling pressure

Abstract

The invention discloses a method and a device for an in-situ penetration test by means of water injection under drilling pressure. The method includes A, drilling a hole on a tested object; B, inserting a water injection pipe, which is provided with a water replenishing container at the upper end, into the drilled hole; C, arranging a sealing plug between the inner wall of the drilled hole and the water injection pipe and forming a sealed test section between the position below the sealing plug and the bottom of the drilled hole; D, fully injecting water into the test section via the water injection pipe until the liquid level reaches the inside of the water replenishing container; E, starting counting and timely replenishing water into the water replenishing container to keep the liquid level in the water replenishing container stable relatively; and F computing penetration flow of the test section within unit time according to the quantity of the replenished water within a period of time and further computing a penetration coefficient of the tested object. The method and the device can be used for testing foundation structures with lower penetration coefficients, head pressure meeting requirements can be provided, stable flow can be tested, and the required penetration coefficient is obtained finally.

Description

technical field [0001] The invention relates to a drilling pressure water injection in-situ seepage test method applicable to various undisturbed foundations and treated foundations, and a test device used for the method. Background technique [0002] In order to determine the permeability coefficient or anti-seepage capacity, in-situ infiltration is required for the undisturbed foundation (such as undisturbed soil, rock) or the treated foundation structure (such as chemically reinforced grouted foundation, mixing piles and underground diaphragm walls of various materials, etc.) Test, the method is usually to carry out water injection test or water pressure test after drilling. [0003] The above-mentioned in-situ permeability test methods all use the undisturbed foundation or the treated foundation structure as the anti-seepage medium, agree on the shape factor of the test object after drilling, use the natural water level or other pressurized methods to provide water head,...

AI Technical Summary

Problems solved by technology

Among them, the water injection test is to use the elevation difference between the ground and the groundwater level to provide the water head. Generally, the water level pressure is limited, and the test and evaluation of the thicker and uneven test objects cannot be carried out in sections; the pressure water test is to use the embolism to drill the hole It is a method of segmenting, providing pressure by water pumps, and using water meters or flowmeters for metering. However, for tests with small permeability coefficients, it is difficult to measure and read flow due to low resolution of water meters or flowmeters, and the pulsation generated by water pumps The water pressure is easy to damage the structure of the test object, making it difficult to obtain a stable flow

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