目前国内标准贯入试验所用的自动落锤多为凸轮式。这种装置在生产实践中存在一些缺点,例如在连续贯入时,往往发生凸轮磨损、失灵,挂不住重锤;有时凸轮小轴被泥沙填塞,不能自由转动,造成重锤上提后 At present, most of the automatic drop hammers used in the national standard penetration test are cam type. Such devices have some shortcomings in production practice. For example, when continuous penetration occurs, cam wear, failure and heavy hammer often occur. Sometimes the small shaft of the cam is padded with sediment and can not be freely rotated, resulting in lifting of the heavy hammer