《资治通鉴·晋纪·晋纪七》
于是趁夜色悄悄逼近距洛阳城七里处，修筑了几层堡垒，从外面运进仓库中的粮谷作为军粮。
乃夜潜进，逼洛城七里，筑垒数重，外引廪谷以足军食。
So he led them under cover of darkness as they stealthily advanced to within seven li of Luoyang, and they built multiple layers of forts, transporting grain from their storehouses to use as military provisions.