The Influence of Physical and Chemical Reactions on Water Leakage in a Multiarch Tunnel

Table 1

Physicochemical reactions and free energy change of the water-rock system.

Number	Reaction volume	Reactant	Physicochemical reaction	(J·mmol^−1)
1	X1	Soda feldspar	NaAlSi3O8 + CO2 + 5.5H2O⟶0.5NaAlSi3 (OH)4 + Na^+ + 2H4SiO4 + HCO3−	79.97
2	X2	Calcareous spar	CaCO3 + CO2 + H2O⟶Ca^2+ + HCO3−	27.66
3	X3	Ca (OH)2	Ca (OH)2 (s)+CO2⟶Ca^2+ + 2HCO3−	−56.77
4	X4	Organic matter	CH2O + O2⟶CO2 + H2O	−405.78
5	X5	CO2	CO2 + H2O⟶H+ + HCO3−	38.9
6	X6	HCO3−	H^+ + HCO3−⟶CO2 + H2O	−38.9
7	X7	Maria glass	KMg3AlSi3O10 (OH)2 + 7H^+ + 0.5H2O⟶0.5Al2Si2O5 (OH)4 + K^+ + 3Mg2+ + 2H4SiO4	348.94
8	X8	Mg (OH)2	Mg (OH)2 (s) + CO2⟶Mg^2+ + 2HCO3−	−53.24
9	X9	Ca^2+	Ca^2+ + Na (s)⟶Na^+ + Ca (s)	30.74
10	X10	Mg^2+	Mg^2+ + 2Na (s)⟶Na^+ + Mg (s)	−70.01