Yuav ua li cas xaiv cov hniav ntawm cellar manhole npog ncig txiav tshuab?

1. Lub txiav precision yuav tsum zoo heev,
2. Kev sib tsoo ntau yam ntawm cov tshuab txiav seam zoo tib yam yuav ua rau kev puas tsuaj rau txoj kev nto, yog li peb yuav tsum xaiv cov cuab yeej txiav,
3. Nws yuav tsum tsim nyog rau ntau qhov chaw xws li cement, asphalt, pob zeb, thiab lwm yam.
4. Lub cav tsim los ntawm hom yuav tsum tau siv, vim hais tias lub cav yog qhov tseem ceeb ntawm tag nrho cov manhole npog ncig txiav tshuab. Lub cav yuav tsum yoog raws thiab yooj yim pib.
5. Xaiv cov khoom los ntawm cov tuam txhab tsis tu ncua thiab zam cov khoom tsis zoo los ntawm cov chaw tsim khoom me.
Zoo, cov ntsiab lus saum toj no yog cov ntsiab lus tseem ceeb ntawm kev xaiv lub manhole npog ncig txiav tshuab. Xaiv cov khoom siv zoo kuj yuav muaj qhov sib npaug ntawm qhov kev tsim kho.