やりたいことが何か判らんが

>>> import numpy as np
>>> a = np.array([[1., 2., 3., 4., 5.],
... [6., 7., 8., 9., 10.],
... [11., 12., 13., 14., 15.]], dtype='float32')
>>> b = np.array([a])
>>> c = a.reshape(3,5,1)
>>> a.shape
(3, 5)
>>> b.shape
(1, 3, 5)
>>> c.shape
(3, 5, 1)