通过黏性土与不同表面粗糙度混凝土板的室内直剪试验，模拟预制桩的界面受力性态。利用微型硅压阻式传感器测定桩-土界面孔隙水压力和土压力的变化，定量分析表面粗糙度对界面抗剪强度参数、界面阻力-剪切位移曲线的影响。试验结果表明：桩-土界面孔隙水压力约占法向应力的10%，实际工程中应考虑；提出桩-土界面阻力的概念，界面阻力由黏性土与混凝土之间黏着力和摩擦力两部分构成，其中摩擦力为界面法向有效土压力与界面摩擦系数的乘积。随着混凝土表面粗糙度的增加，界面黏着力增大且逐渐接近黏土自身黏聚力。表面粗糙度对界面摩擦系数影响较小，但对界面阻力有一定影响，桩-土界面峰值阻力和剪切位移均随粗糙度的增加而增大。试验结果能够为桩基工程的设计、施工与检测提供参考依据。

The interfacial force of the precast pile with different roughness was measured by indoor direct shear test in clayey soil. The changes of the pore water pressure and soil pressure on the pile-soil interface were monitored by miniature piezo-resistive sensors. The influences of interfacial roughness on interface shear strength parameter, interface resistance-shearing displacement curves were qualitatively analyzed. The results show that the percentage of normal stress accounted by pore water stress on pile-soil interface is about 10%, which is supposed to be taken into consideration in practical projects. The concept of pile-soil interface resistance is presented and the resistance is contributed by adhesive force and friction force between clayey soil and concrete. the friction force is the product of the normal effective soil stress and friction coefficient on the interface. As the interfacial roughness of the concrete increases, the interfacial adhesive force increases and gradually closes to clayey soil’s inherent adhesive force. The interfacial roughness slightly impacts on interfacial friction coefficient and interface resistance: the ultimate interface resistance and shearing displacement increase with the increase of the roughness. The results provide references to the design, construction and detection of the pile foundation engineering.