Improved construction technology of CFG (cement fIying-ash gravel) pile

Abstract

The invention discloses an improves construction technology of a CFG (cement fIying-ash gravel) pile, which is characterized by comprising the following steps of: A, punching and plunging a pile pipe; B, arranging a high-pressure grouting pipe into the plunged pile pipe, and adding aggregates, wherein the aggregates can be gravels or mixed materials of gravels and sands which are prepared in proportion; C, pulling the pile pipe out, and tamping the aggregates inside a hole; D, building a plurality of pile points on a plurality of piling positions by repeating the steps; E, cleaning the hole of each pile point and grouting the hole of each pile point by pressure, i.e. firstly injecting water into the hole through the high-pressure grouting pipe, and cleaning the hole and the aggregates inside the hole till clear water overflows out of an orifice; and then grouting pulverized fuel ash cement paste or pulverized fuel ash cement plaster into the hole filled with the aggregates by using the high-pressure grouting pipe till grouts are burst out of the orifice. The invention can effectively enhance the carrying capacity of the CFG pile and the bonding degree of the pile and soil bodies and effectively prevent the defects of necking down, pile breakage and pile body clamping soil, has extensive application, and can be suitable for various geological conditions.

Description

Technical field [0001] The invention relates to an improved construction technology of CFG piles in roadbed engineering. Background technique [0002] Cement Fly-ash Gravel pile (Cement Fly-ash Gravel pile) is developed on the technology of plain concrete pile foundation, mainly composed of crushed stone, stone chips (or sand), fly ash and mixed with appropriate amount of cement A pile with a certain bonding strength mixed with water. CFG pile composite foundation technology has been widely used in expressways. The construction quality of CFG piles directly affects the post-construction settlement of the roadbed, the traffic service level after the highway is built, and the stability of the entire roadbed. Therefore, controlling the construction quality of CFG piles is a key link in CFG pile composite foundation. [0003] At present, the construction of CFG piles is mainly vibratory sinking pipe pouring. The main construction technology is to first drill down the sinking pipe in ...

AI Technical Summary

Problems solved by technology

[0003] At present, the construction of CFG piles is mainly vibratory sinking tube grouting construction. The main technology of its construction is to drill down the sinking tube at the foundation section that needs piling, and then put gravel, stone chips (or sand), fly ash And mixed with an appropriate amount of cement and water according to a certain proportion to mix and stir into concrete piles, and then directly sent into the immersed tube, and piles can be formed at one time. Because of its high work efficiency, low cost, flexibility and convenience, it is popular at home and abroad. attention, but this construction technique has defects to a certain extent on the quality of CFG piles: (1) The strength of the soil is reduced due to construction disturbance

When the pile tube sinks and encounters a very hard ground, or reaches the bearing layer, the pile tube will bounce back and forth upwards, and the valve may open and close at times, so that the soil will be grasped into the tube; If the reverse insertion method is used, since the verticality of the pile tube is difficult to ensure, the reverse insertion will easily mix the soil and the pile body material, resulting in defects such as soil mixed with the pile body, which seriously affects the bearing capacity of the CFG pile.

[0004] To sum up, the quality of vibration-immersed CFG piles is difficult to control during construction, and there are many defects, so it is necessary to improve its construction technology

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