为探究结泥饼过程中土体内部的黏聚力、土体与金属刀盘间的黏附力2种力学行为，对比分析不同剪切方式下土样的剪切破坏模式，采用自行研制的旋转转矩试验装置，分别对纯伊利土、纯高岭土、纯蒙脱土及含砂伊利土4种土样进行十字板和圆盘剪切转矩试验。试验结果表明： 1）随着法向压力的增大，十字板剪切和圆盘剪切的峰值转矩及残余转矩均随之升高，土样的峰值转矩与压力表现出较强的线性相关。2）相比纯伊利土，含砂伊利土峰值转矩更高，残余转矩较低。3）在2种剪切方式下，3种土样的峰值转矩和残余转矩均表现出显著的线性相关，其中，土样的峰值转矩和残余转矩均表现为蒙脱土＞伊利土＞高岭土，蒙脱土堵塞风险最高。4）十字板剪切转矩和圆盘剪切转矩线性相关，对于同种土样，十字板剪切和圆盘剪切峰值转矩拟合直线斜率和残余转矩拟合直线斜率基本相同。当土样发生堵塞风险最高，即土样稠度指数为0.625时，剪切破坏主要发生在土体内部，土体黏聚力小于土体与金属刀盘间的黏附力。
The authors investigate the
mechanical behavior of internal soil cohesion and the adhesion between clay
soils and metal cutterheads during mud cake formation. The shear failure modes
of soil samples under two shear methods are analyzed. A self-developed rotational torque test device is used to conduct vane and
plate shear tests on four types of soil: pure illite, pure kaolinite, pure
montmorillonite, and sand-illite mixtures. The findings
are as follows: (1) With increasing normal pressure, both peak and residual
torque increase for vane and plate shear, with peak torque showing a strong
linear correlation with pressure. (2) Compared to pure illite, sand-illite mixtures exhibit higher peak torque and lower residual
torque. (3) For illite, kaolinite, and montmorillonite, peak and residual
torque under both shear methods exhibit significant linear correlations;
montmorillonite yields the highest torque values, followed by illite and then
kaolinite, indicating montmorillonite poses the greatest clogging risk. (4)
Vane and plate shear torque values are linearly correlated. For the same soil,
the slopes of fitted lines for both peak and residual torque are nearly
identical under both test methods. When clogging risk is highest, i.e., when
the consistency index reaches 0.625, shear failure occurs within the soil, and
cohesion is lower than adhesion to the cutterhead.
