Abstract: A method for constructing a fixed monitoring pile for a mining area with a high phreatic water level includes: S1: prefabricating a pile foundation body, where the pile foundation body has a columnar structure, and a plurality of extension connection ports are provided at an outer side and a bottom of the pile foundation body; and S2: digging a foundation pit at a designated monitoring point; combining the pile foundation body with an extension body to form a fixed monitoring pile; placing the fixed monitoring pile into the foundation pit, such that a bottom extension body and a side extension body are inserted into the pit foundation; and backfilling and compacting. The method increases the affinity between the fixed monitoring pile and a loose layer and strengthens the fixed monitoring pile to prevent it from loosening, thereby improving measurement accuracy.

Abstract: A method for constructing a fixed monitoring pile for a mining area with a high phreatic water level includes: S1: prefabricating a pile foundation body, where the pile foundation body has a columnar structure, and a plurality of extension connection ports are provided at an outer side and a bottom of the pile foundation body; and S2: digging a foundation pit at a designated monitoring point; combining the pile foundation body with an extension body to form a fixed monitoring pile; placing the fixed monitoring pile into the foundation pit, such that a bottom extension body and a side extension body are inserted into the pit foundation; and backfilling and compacting. The method increases the affinity between the fixed monitoring pile and a loose layer and strengthens the fixed monitoring pile to prevent it from loosening, thereby improving measurement accuracy.

Abstract: A level instrument for surveying a mining subsidence zone in a coal mining area includes a bottom plate, a leveling mechanism, a lifting mechanism, and a level instrument body, where the leveling mechanism is provided on the bottom plate, the lifting mechanism is provided on the leveling mechanism, and the level instrument body is provided on the lifting mechanism. A surveying method using the level instrument is further provided. The level instrument is placed at a surveying location through the bottom plate, a levelness of the level instrument body is directly adjusted through the leveling mechanism below the level instrument body, and a height of the level instrument body is directly adjusted through the lifting mechanism. In this way, the operation process of the level instrument is simplified, and the overall surveying efficiency is improved.