Grouting Reinforcement of Large Building Foundation over Old Gob Areas: A Case Study in Huaibei Mining Area, China

Table 6

Characteristics of the boreholes before and after grouting.

Time	Borehole	Leakage observation	Drill felling	Wind inhalation
Before grouting	K3	99.5 m to end all lost; leakage more than 15 m^3/h	No	Yes
	K6	101.5 m to end all lost; leakage more than 15 m^3/h	No	Yes
	K7	89.9 m to end all lost; leakage more than 15 m^3/h	Yes	Yes
After grouting	J1	No leaking	No	No
	J2	89.9 m to end a little lost; leakage only 0.54 m^3/h	No	No
	J4	No leaking	No	No