Presently I would say the satandard practice where feasible is to use anchors to the ground of walls previously made with the temporary help of bentonite. As you deepen, you anchor in the required amount. Then, if yor build fllors able to sustain the compression of the earth against the walls you may (and sometimes is required) release the (then) temporary anchors.
However ordinance is adversary in downtown to this, since there are standing facilities that may result damaged.
Then piles as the walls may be done before, and instead of any unreliable buttressing or complicated in compression scaffolding and structural members (I have seen ugly 20 m span or so near horizontal arches helping to stand earth pressure) you may build the underground floors on the piles and walls from top (surface) down (to deepest slab). This way you are using the final structure to hold the push inwards your underground levels.
PTI has a publication on underground anchors
Recommendations for Prestressed Rock and Soil AnchorsPTI
Another interesting is
Recomendaciones para el proyecto, construcción y control de anclajes al terreno H.P. 8-96
ATEP / IETCC / CICCP
Look also
Deep Excavations
Malcom Puller