密实地层中碎石桩施工工艺研究

Study onconstruction technology of gravel piles in dense ground

碎石桩是指通过向地层中夯(填)入碎石料后在地基中形成的碎石料组成的桩体。在密实地层中沉管时,沉管端口、沉管外侧所受到的阻力大,无法把沉管下沉到设计深度,导致无法施工碎石桩。为解决这一问题,以云南省大理某项目为例,采用了长螺旋钻机引孔后用振动沉管工艺进行施工。当长螺旋钻机引孔穿越密实地层后,采用振动沉管打桩机,按照沉管、填料加密,直至碎石桩设计深度,解决了密实地层条件下无法施工振动沉管碎石桩的难题,提高了地基的承载力。

A gravel pile is composed of crushed stone which is filled into formation.When bushing is immersed in the dense formation,the resistance of bushing port and bushing outer side is large,and bushing cannot be sunk to the design depth,resulting in the impossibility to construct the gravel pile.In order to solve the problem mentioned above,taking a project in Dali,Yunnan Province as an example,a long auger drilling machine was used to construct the hole before the vibration immersed tube process.After the long auger drilling hole passed through the dense stratum,the vibrating immersed pile driver is used,according to the immersed pipe and the packing encryption,until the design depth of the gravel pile,which solves the problem that the vibrating immersed stone gravel pile can not be constructed under the dense stratum condition,and improves the bearing capacity of the foundation.