מלכים ב יט:לב פירוש: רש״י וMetzudat Zion

He will not advance upon it. He will not set a shield before it.²⁷The first soldiers attacking a city were the shield bearers.—Radak

Sent out (as in shoot).

A ramp. A heap of earth to raise a mount upon which to stand to wage war against the city, and because one presses it down and beats it with sticks and sledge hammers, so that it becomes trodden and pressed down with strength, it is called סוללה, an expression of, “Beat down [=סולו], beat down [=סולו] the highway.”²⁸Yeshayohu 62:10. See also II Shmuel 20:15.