JavaScript (Node.js), 45 bytes

_=>`_|__`.repeat(175).match(/.{70}/g).join`
`

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#Explanation :

_ =>                    // lambda function (argument passed to save a byte)
    `_|__`              // simple enough
    .repeat(175)        // repeat the above mentioned shape 175 times
    .match(/.{70}/g)    // simple regexp to match a shape 70 (something :) ) long 
    .join`\n`           // and join them on a new line

Simple enough.

#Alternate version :

JavaScript (Node.js), 714 bytes

_=>`_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__`

Try it online!

No explanation required. Simple hard coded.

JavaScript (Node.js), 45 bytes

_=>`_|__`.repeat(175).match(/.{70}/g).join`
`

Try it online!

Explanation :

_ =>                    // lambda function (argument passed to save a byte)
    `_|__`              // simple enough
    .repeat(175)        // repeat the above mentioned shape 175 times
    .match(/.{70}/g)    // simple regexp to match a shape 70 (something :) ) long 
    .join`\n`           // and join them on a new line

Simple enough.

Alternate version :

JavaScript (Node.js), 714 bytes

_=>`_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__
_|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|
___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|___|__`

Try it online!

No explanation required. Simple hard coded.