Помогите, пожалуйста, перевести на русский язык While the use of a TNM relieves the need for large numbers of workes at increased pressure, a caisson system is sometimes formed at the cutting head. Workers entering this space for inspection, maintenance and repair need to be mediacally cleared as "fit to dive" and trained in the operation of the lock. Modern TBMs typically have an integrated shield. The choice of a single or double shielded TBM depends on the type of rock strata and the excavation speed required. Double shielded TBMs are normally used in unstable rock strata, or where a high rate of advancement is required. Single shielded TBMs, which are less expensive, are more suitable to hard rock strata.