Diaphragm walls (slurry trenches) is more needed nowadays in urban areas and crowded cities where 
underground constructions as subways, deep basements and utilities as pump stations, underground tanks and tunnels 
mainly depending on drilling methodology using slurry trenches. Many researchers and different codes of buildings 
have discussed the risk issues related to design analysis or materials but hardly find scientific researches discussing 
quality control on site during construction process and its effect on the overall quality of the work needed. Some of 
these issues is geometrical imperfections such as the positioning error of drilling rigs during trenching, small seepage 
passages through the diaphragm wall may occasionally occur, which will undermine its water-tightness and lead to 
significant leakages. This study focus on examination of penetration of seepage passages and it further quantitatively 
estimates the flow rate through the diaphragm wall under certain circumstances.