1.Coal Mining and Designing Department，Tiandi Science and Technology Co.，Ltd.，Beijing ，China；2.Coal Mining and Designing Research Branch，China Coal Research Institute，Beijing ，China

针对我国煤矿很多矿区锚杆托盘下加木垫板比较普遍的现象，采用实验室试验的方法，利用自行研制的锚杆支护应力场试验台，对木垫板作用下锚杆预紧力损失、预紧转矩转化以及支护预应力场分布情况进行了研究，并与金属托盘进行比对分析，揭示了木垫板对锚杆预应力的影响规律。研究结果表明：在干燥环境下，加木垫板锚杆预应力1 h损失率高达23%，锚杆预紧转矩转化为预紧力的系数降低23%，锚杆支护在围岩中形成的预应力场范围大幅减小，各应力等值线面积平均降低27%，预应力峰值降低38%；同时指出，在井下湿度超过90%的环境中，木垫板对锚杆工作荷载的影响将会大幅增加。

Aiming at the common phenomenon of adding wooden plate under the bolt trays of many mines in China, the laboratory test method was used to reveal the influence of wooden plate on the pre-stress of bolt by using the self-developed bolt support stress field test rig. The pre-stress loss, preload torque conversion and pre-stress distribution of the bolt under the action of the wooden plate were studied and compared with the metal trays. The results show that in the dry environment, the first hour loss rate of the bolt prestress of the wooden plate is up to 23%, and the coefficient of the preload torque convert to pre-stress of the bolt is reduced by 23%. The range of pre-stress fields formed by bolt support in the surrounding rock is greatly reduced, the area of each stress contour is reduced by 27% on average, and the peak of pre-stress is reduced by 38%. It is also pointed out that in the environment where the humidity of the mine exceeds 90%, the influence of the wooden plate on the working load of the bolt will be greatly increased.