为探究复合地层中盾构刀盘的掘进速率及受力特性，基于连续-非连续单元法（CDEM），建立盾构-岩土体这一完整系统的数值计算模型。通过在CDEM中引入简单有限体积法、虚拟质量法、单元溶蚀算法等系列算法，实现盾构刀盘掘进全过程的三维模拟。建立5种刀盘面花岗岩占比的刀盘破岩数值模型，并对不同刀盘面花岗岩占比下的刀盘进尺、掘进速率、平均转矩、平均倾覆力矩等进行详细分析。数值模拟结果表明： 1）在某一特定复合地层中掘进时，随着掘进时间增加，刀盘进尺基本呈线性增大的趋势，但进尺曲线中平缓段及速升段交替循环出现； 2）刀盘面花岗岩占比由0增大至100%，掌子面处拉伸破坏单元增加，剪切破坏单元减少，且刀盘的掘进速率呈指数衰减趋势，掘进速率降低88.7%； 3）刀盘面花岗岩占比由0增大至100%，平均转矩值逐渐增大，增大比例为117.5%，平均倾覆力矩值则呈现先增大后减小的趋势，且在花岗岩占比为50%时最大。

In order to study the advancing speed and force characteristics of shield cutterhead in upper soft and lower hard strata, a numerical computational model of shieldrock mass is established based on continuum discontinuum element method (CDEM). By introducing a series of algorithms to CDEM, such as simple FVM, virtual mass method and element erosion algorithm, the 3D simulation of tunneling process of shield cutterhead is realized. Five numerical models for cutterheadrock system with different granite ratios are established, and the cutting depth, advancing speed, average torque and average bending moment are analyzed in detail. The numerical simulation results show that: (1) With the increase of excavation time, the cutting depth increases linearly when boring in a particular composite stratum; but in the footage curve, there is an alternate cycle between smooth and fast rising sections. (2) When the granite ratio increases from 0 to 100%, the tensile failure element near tunnel face increases, while the shear failure element decreases; meanwhile, the advancing speed of the cutterhead shows a trend of exponential decay, and the advancing speed reduces by 88.7%. (3) When the granite ratio increases from 0 to 100%, the average torque increases gradually by 117.5%; the average bending moment firstly increases and then decreases, and the peak occurs when granite ratio is 50%.