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| Research on Assessing of Integrity of Concrete Bored Pile and Thickness of Sediment |
| CHANG Ju-you, LIU Zu-fu, GUO Jiang-bo, YANG Wen-jie |
| China Railway Eryuan Sichuan Zhiyuan Engineering Testing Co. Ltd, Chengdu, Sichuan 610031, China |
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Abstract The reflection wave method is used in assessing of integrity concrete pile and thickness of sediment, the measured reflection wave curves must first determine the pile end and the speed value, but the determine of the pile end and speed values is affected by several factors, sometimes resulting in a miscarriage of justice. Therefore the research of assessing of integrity concrete pile and thickness of sediment is necessary.Research conclusions:(1)For the bored friction piles, the pile end reflection wave curves showed the positive direction characteristic; For the shorter bored end bearing piles, and the longer bored end bearing pile that there is a horizontal strata under the end, the pile end reflection wave curves showed the opposite direction characteristics; For the longer bored end bearing pile that there is dip strata under pile end, and the strength of concrete pile body equal the strength of the rock under pile end, the pile end reflection wave curves showed no reflection of pile bottom characteristic. (2) Concrete slump of pile should be controlled in the upper limit that is 180 mm, and the same area, the same environment, the same material, the same grade concrete model pile that the upper limit of the slump is 180 mm, the lower limit is 220 mm is used to detect in reflected wave velocity, gets the upper critical value and the lower critical value of reflective concrete pile wave velocity, and the measured pile speed value should be in its critical value, higher than the upper critical value is the construction of pile length not exceeding the design pile length, less than the lower critical value is defective piles. (3) The longer bored friction pile end reflection wave curves forward amplitude is larger than the short pile end reflection wave curves forward amplitude, there is the soft soil in the longer pile end. (4)The sediment thickness should be controlled in allowable range, to ensure no sediment under the pile end during concrete pouring when the role of impact force in the acceleration of gravity. (5) The results can be applied to the railway foundation concrete pile.
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Received: 29 March 2014
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2014, Vol. 31 
