Rock engaged combined pile and its construction method

Abstract

The rock engaged combined pile includes pile section inside soil layer and pile section inside rock formation combined together and includes also stuffing. The pile section inside soil layer may be prefabricated reinforced concrete pipe or steel pipe with grouted stuffing or steel pipe pile with outer coating stuffing. The pile section inside rock formation may be steel cage, steel member or prefabricated reinforced concrete member or their combination filled with stuffing. The pile section inside rock formation has its load diffused to deep rock formation via the combination of the stuffing to rock hole wall. Owing to the large contact area of the stuffing, the pile of the present invention can provide large anchoring force.

Description

technical field [0001] The invention relates to a pile as a deep foundation of a building, especially a composite pile that relies on grouting materials, prefabricated piles, and the cohesive force of the inner wall of a rock hole to gradually spread the load to the bearing rock layer along the vertical direction; The contact area and mechanical bite force between the prefabricated component and the grouting material in the rock hole enable the rock hole to provide the rock-socketed composite pile with the maximum bearing capacity and its construction method. Background technique [0002] The prefabricated piles used in the general pile foundation are all connected with the prefabricated reinforced concrete piles or section steel piles one by one on site with a pile driver, and the soil is squeezed into the design depth. The pile head load is supported by the friction between the pile body and the surrounding soil and the bearing capacity of the bearing layer at the bottom o...

AI Technical Summary

Problems solved by technology

The disadvantage of this is that the construction noise is large and the vibration is severe; the second is that the pile body is easily damaged or weakened under the violent and continuous impact of the piling hammer; the third is the ability of the squeezed soil to drive the pile to penetrate the hard soil layer Poor, when some piles of the foundation have to be located on the local hard soil layer, it is easy to cause uneven settlement of the building and tilt; Fourth, under the same bearing capacity, the self-weight of the prefabricated concrete pile is usually equal to that of the steel pile 2 to 3 times, the energy of the required pile hammer has been greatly increased, resulting in the inability of general piling machinery to drive the pile into the corresponding bearing layer; fifth, the piling must be driven in strict order, otherwise the pile driven in the later stage will "put the pile into the corresponding bearing layer". Squeeze away from the original position, because the soil extrusion stress of the piles driven in the early stage will not dissipate in a short time, which makes it difficult to drive the piles later, and has to be driven back, which delays the construction period

Construction costs also increase accordingly

[0005] 2. The shaped steel piles in the rock holes have not been specially processed, and their surface area has not been increased. The bonding force between the smooth surface and the grouting material is not ideal, thus requiring deeper rock holes and increasing the construction cost

When the grouting material is improperly configured to shrink or leave impurities, it will cause a weak link in the rock hole pile section, resulting in a decrease in bearing capacity

[0006] 3. Due to the high technical requirements for the production of H-shaped steel and the shortage of resources, it cannot be produced by ordinary manufacturers, so the cost of the steel pile body is generally higher than that of the reinforced concrete pile body

[0007] Although prefabricated piles and cast-in-situ concrete parts are also included in the design of some composite piles, their load-bearing mechanism is still the same as that of traditional bored piles, that is, the load is transmitted by the local pressure of the contact level between the pile bottom and the rock. Typical end piles are only replaced by prefabricated concrete piles (see JP-127054), and it is always difficult to avoid the influence of sediment on the quality of piles

Because the strength of concrete is usually greater than that of rock, it is necessary to expand the bottom if the full bearing capacity of the pile body is to be exerted. However, the cost of machinery used for bottom expansion is high, the operation technology requirements are high, and pipe sticking accidents are prone to occur, and the actual bottom expansion size is also large. hard to control

The positioning of the prefabricated pile sections was also very difficult as there were no reinforcements extending straight to the rock face

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