针对钻孔灌桩桩在成孔过程中的成孔卸荷问题,基于统一强度理论对孔周土体的应力场和位移场进行分析.推导了孔周塑性区起始深度、塑性区半径的解析解,并通过算例分析了泥浆比重、土体强度参数和统一强度理论参数的取值对各解析解的影响.结果表明:孔内泥浆比重直接影响着孔周土体卸荷程度.泥浆比重越大,孔周塑性区起始深度越深,塑性区范围越小.当泥浆比重大至某一定值后孔周土体不再卸荷,而是慢慢由卸荷缩孔过渡至加荷扩孔.%The solutions based on unified strength theory were presented for the stress field and displacement field around the hole of bored pile during the process of excavating. This paper derived the analytical solutions for depth of initial plastic zone, the outer radius of plastic zone. The effects of mud' s density, the strength of soil and unified strength parameterb on the solutions were analyzed through a case. The results show; the mud pressure act on the hole-wall dominates the unloading level around the hole. The initial plastic depth and plastic zone shrink as mud weight increase. The plastic zone diminishes as mud density gain a definite value, which as transient point between unloading and loading.
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