MATL, 15 bytes
'_|__'700:)70e!
Of course, you can Try it online! Explanation:
'_|__' % Put a brick on the stack
700 % 700 times
:) % Makes a happy mason...
70e! % Secret freemason code
OK, actually, it works as follows:
'_|__' % Put the first bit of the string on the stack
700: % Put 1, 2, ..., 700 on the stack as array
) % Index into the string, modularly. Result: '_|___|__ ... __'
70e % Reshape into 70 rows (and consequently, 10 columns)
! % Transpose to get the desired output.