In order to improve the bearing capacity of foundations,some new grouting methods and techniques have been employed in the consolidation grouting of backfilled sand-cobble stratum,including casing drilling,filling sand in a perforated pipe,protecting the wall with SM plant glue,forming a hole by diamond drilling and grouting in stages.

During the investigation,the perpendicularity of the drilling hole can not be guaranteed by the conventional drilling method firstly used,and then the technology of SM vegetable glue drilling with multi-casting drilling bit is decided to be used.