132. Safety measures for tunnelling operation.- The employer shall ensure at a construction site of a building or other construction work that,- (a) where there is a danger of falling or sliding of material from the roof face or wall of a tunnel, adequate measures such as shoring, supporting by means of rock bolts, segments or steel sets are taken for the safety of building workers; (b) the excavated areas are made safe by use of suitably designed and installed steel sets, rock bolts or similar other safe means; (c) the responsible person referred to in rule 121 examines and inspects the workplaces in a tunnel before the commencement of work in such tunnel, and at regular intervals thereafter, to ensure safety of the building workers in such tunnel; (d) the portal areas of a tunnel with loose soil or rock, likely to cause injury to a person are adequately protected with supports. | 
