Formation of groundwater-induced damage in Zhu Yuelian’s tomb and protection methods

Zhu Yuelian’s tomb has been exposed to groundwater for many years, and this exposure has caused many defects, including erosion, encrustation, patina, and spot marks related to groundwater, seriously affecting the artistic and ornamental value of cultural relics. In this study, high-density microelectrode spacing resistivity and ultrasonic transverse wave reflection were used to detect hidden damage in the burial chamber, and the results revealed hidden damage, corrosion, cracks, and pores in the surrounding geological body, concealed cracks in the sidewalls, and internal defects in the columns. An outdoor high-density resistivity test and hydrological observation experiment indicated that the tomb is located in a weakly permeable aquifer, and the groundwater head has been higher than the bottom of the tomb for many years. Natural groundwater flows from northeast to southwest in the aquifer, and the tomb forms an artificial concave cone, causing groundwater around the area to continually flow into the tomb. A chemical composition analysis of the groundwater and scale revealed that the groundwater within the tomb area is slightly corrosive, and the groundwater seepage along the fissures of the compacted layer induces damage. The three-dimensional (3D) seepage numerical simulation results indicated that the combined use of drainage and impervious curtains can cause the water head in the curtain to drop significantly and control the water head to be lower than 8 m from the bottom floor of the tomb, meeting the requirements for seepage prevention and protection of the tomb without long-term maintenance.