CAJ | 학술논문

为研究带有垫层的素混凝土桩复合地基中桩身轴力、桩侧摩阻力的分布及发展过程，设计了一组足比例尺单桩复合地基试验，在桩身内埋设钢弦式应力计测出了桩身轴力，并由此得出桩侧摩阻力。从实测结果与散体桩、无垫层带台单桩的桩身轴力、侧摩阻力分布对比分析可以看出，三者传力机理是不同的。与散体桩相比，素混凝土桩复合地基中荷载沿桩身全长传递。与无垫层带台单桩相比，桩侧摩阻力从加荷开始在桩周上部土层即出现负摩阻，使得桩身轴力最大点不在桩顶而在中性点处。带有垫层的素混凝土桩复合地基中桩侧负摩阻力的大小随荷载加大而变小，同时中性点位置逐渐上移，相当一部分上部土层的摩阻力随着荷载的加大由负摩阻力逐渐变为正摩阻力。该负摩阻力使桩从加荷开始就承担较大荷载，并使桩下部的摩阻力也能得到充分发挥，进而使桩在全过程都发挥了作用。同时，桩周土体的承载力也得到增强。
위연구대유점층적소혼응토장복합지기중장신축력、장측마조력적분포급발전과정，설계료일조족비례척단장복합지기시험，재장신내매설강현식응력계측출료장신축력，병유차득출장측마조력。종실측결과여산체장、무점층대태단장적장신축력、측마조력분포대비분석가이간출，삼자전력궤리시불동적。여산체장상비，소혼응토장복합지기중하재연장신전장전체。여무점층대태단장상비，장측마조력종가하개시재장주상부토층즉출현부마조，사득장신축력최대점불재장정이재중성점처。대유점층적소혼응토장복합지기중장측부마조력적대소수하재가대이변소，동시중성점위치축점상이，상당일부분상부토층적마조력수착하재적가대유부마조력축점변위정마조력。해부마조력사장종가하개시취승담교대하재，병사장하부적마조력야능득도충분발휘，진이사장재전과정도발휘료작용。동시，장주토체적승재력야득도증강。
The distribution and change of axial force of piles and pile friction in composite grounds are very important characters of composite grounds. The axial force of piles was measured by means of in-situ test and on the basis of this the pile friction was worked out. Contrasted with compressible piles and compound piles, the mechanism of concrete piles is different. Contrasted with compressible piles, the loads on concrete piles can be transferred though the whole piles. Contrasted with compound piles, the concrete piles provide negative pile friction around upper piles that leads to the force of piles top is not the maximum. The maximum is at neutrality point. With loads increasing, the negative pile friction decreases and the neutrality point moves upward and part of the negative pile friction transforms into a positive pile friction. It is the pile friction that makes piles bear more loads at the beginning of loading and makes pile friction of lower piles be fully utilized. Thus the interaction between piles and surrounding soil is present in the process of loading. At the same time, the bearing capacity of soil around piles is reinforced.