ansys请教。。。

/clear
/prep7
et,1,solid45
et,2,mesh200,6

!土体材料参数
mp,ex,1,3.49e6
mp,prxy,1,0.35
mp,dens,1,1828
mp,ex,2,20.6e6
mp,prxy,2,0.30
mp,dens,2,2160
mp,ex,3,500e6
mp,prxy,3,0.33
mp,dens,2,2160
!管片材料参数，管片衬砌按各向同性计算
mp,ex,4,27.6e9
mp,prxy,4,0.2
mp,dens,4,2500
!注浆层，参数按水泥土取值
mp,ex,5,1e9
mp,prxy,5,0.2
mp,dens,5,2100

!在隧道中心线定义局部坐标，便于后面的实体选取
local,11,0,0,0,0
local,12,1,0,0,0
csys,11
wpcsys,-1
cyl4,,,,,2.7,90
cyl4,0,0,2.7,0,3,90
cyl4,0,0,3,0,3.2,90
rectng,0,4.5,0,4.5
aovlap,all
nummrg,all
numcmp,all
rectng,4.5,31.5,0,4.5
nummrg,all
numcmp,all

mshkey,1
type,2
lesize,1,,,6
lesize,2,,,6
lesize,3,,,6
amesh,1
lesize,4,,,6
lesize,8,,,2
lesize,9,,,2
amesh,2
lesize,5,,,6
lesize,10,,,1
lesize,11,,,1
amesh,3
lesize,12,,,3
lesize,13,,,3
lesize,6,,,3
lesize,7,,,3
lesize,14,,,8,2
lesize,16,,,8,0.5
amap,4,7,6,8,10
amap,5,9,8,11,12
!利用对称性，得到下半部分模型
arsym,y,all
nummrg,all
numcmp,all
allsel,all
!建立隧道下方土层模型
rectng,0,4.5,-4.5,-26
rectng,4.5,31.5,-4.5,-26
nummrg,all


前面的没问题的 一但输入 最后一行的nummrg,all就提示
unmeshed line 34 is merged into meshed line 27.
请教ansys高手解答。。。 谢谢