Model Investigation of Anti-seepage Measures for the Foundation of a Heritage Building Based on Soil Improvement

The brick-earth foundation of the Bell Tower in Xi'an, which has been preserved for about 600 years since the Ming Dynasty, has suffered from different degrees of infiltration and leakage from rainfall, caused by the ageing and cracking of the anti-seepage layer (cement mortar, lime soil and asphalt felt) on the top of the foundation and the loss of clay particles in the rammed soil. In order to address this problem, two common seepage control measures were evaluated by using laboratory tests and model tests, one by replacing the modified soil and the other by compacting the rammed earth. For the former, the shear strength, permeability, and microstructural properties of six types of modified soils were studied when using traditional modified soil for reclamation. Anti-seepage effects of modified soils were compared through four characteristic parameters such as maximum increment of volumetric water content, residual volumetric water content, the infiltration duration, average increment rate. Adding sticky rice juice, lime water and tung oil into the plain soil (PS) or tabia is an optimal option. For the latter, it is difficult to achieve a good anti-seepage effect only by increasing the density of rammed earth. Thus, it is recommended to use the optimal soil modification option as the anti-seepage measure.

Automated summary

The brick-earth foundation of the Bell Tower in Xi'an, which has been preserved for about 600 years since the Ming Dynasty, has faced infiltration and leakage issues due to ageing and cracking of the anti-seepage layer on top and the loss of clay particles in the rammed soil. Two common seepage control measures were evaluated, with the optimal option being the addition of sticky rice juice, lime water and tung oil into the plain soil. Increasing the density of rammed earth alone did not achieve a good anti-seepage effect, recommending the use of soil modification as a measure instead.