Solidifying graves

The Kitaabs of Fiqh categorically state that it is not permissible to solidify the grave using bricks or concrete etc. Yes, we do acknowledge that when we experience heavy rainfall then many graves tend to sink, or the soil is washed away. However, such occurrences rarely take place, such as, in the months of summer when heavy rainfall is generally experienced. In such instances, the graves can be refilled and restored to its original condition within a few days, or a week (although some difficulty will be experienced in doing so). In conclusion, since the difficulty of restoring graves occurs just once or twice in a year (generally) and is not a continuous occurrence throughout the year, it will not be permissible to solidify the graves (by placing bricks and concreting the edges) due to the general prohibition mentioned in the Hadith and Kitaabs of Fiqh.