5.控制测量对贯通精度影响的限值高横向中误差(mm)程相邻两开挖洞口间长度(km)中测量部位误差4~88~1010~1317~20<413~17mm±1洞外304560901201508±1洞内4060801201602007±2洞外、洞50751001502002505内总影响