gravel system的用法和樣例：
例句
- Karez water is leaking through the mountain snow water flow inside the gravel layer of diving.
坎兒井的水源就是山上的雪水經(jīng)過(guò)滲漏流礫石層里的潛水。 - The conclusion is that the high-pressure gunite technique applied to 30 m thick of sand and gravel layer is feasible.
通過(guò)本次經(jīng)驗為在深厚層砂卵礫石層中進(jìn)行高噴灌漿施工提供借鑒。
