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为研究灌注桩护壁套管高频振动贯入过程中土塞效应机理,利用ABAQUS有限元软件建立护壁套管高频振动贯入全过程的有限元-无限元耦合模型,对土拱效应、土塞闭塞程度及土塞影响因素等进行分析。结果表明:护壁套管高频振动贯入过程中套管端部土塞形成土拱,导致内侧摩阻力显著增大,此段土塞承担了内侧摩阻力的主要部分;护壁套管高频振动贯入过程中剪切面土体在反复剪切作用下,土体强度和胶结力降低,导致土塞处于不完全闭塞程度,贯入阻力也比其他贯入方式的阻力要小;内侧摩阻力随振动频率增大而减小,当振动频率达到一定值之后,振动频率对内侧摩阻力的影响不明显。内侧摩阻力随套管外径增大而逐渐减小;砂土中内侧摩阻力相较于黏土大,且随密实度增大而减小;同时,对护壁套管高频振动贯入过程中土塞阻力分布规律进行分析,给出了相应的简化计算公式。
In order to study the mechanism of soil plug effect during high-frequency vibration penetration of cast-in-place bored piles, the finite element-infinite element coupled model of high frequency vibration penetrating wall bushing was established by ABAQUS finite element software. The soil arching effect, Plug the degree of occlusion and soil plug the impact of factors such as analysis. The results show that soil arching is formed by the soil plug at the end of the bushing during high-frequency vibration penetration of the bushing, resulting in a significant increase in the frictional resistance inside the bushing. The soil plug takes the major part of the friction resistance inside the bushing. Under the action of repeated shearing, the strength and the cementation of the soil decrease due to the repeated shear, which leads to the incomplete occlusion of the earth plug and the smaller penetration resistance than the other penetrating methods. The internal frictional resistance With the vibration frequency increases and decreases, when the vibration frequency reaches a certain value, the vibration frequency on the inboard frictional resistance is not obvious. The inner frictional resistance decreases with the increase of the outer diameter of the casing; the frictional resistance in the sand is larger than that of the clay and decreases with the increase of the compactness; meanwhile, Soil resistance distribution law is analyzed, and the corresponding simplified calculation formula is given.