A method for connecting in a liquid-tight manner cooperating lock halves of a locking device of adjacent wall sections of a multi-sectioned wall introduced into a suspension includes providing a first lock half as an inner profiled member and a second lock half as an outer profiled member. The inner profiled member is inserted into the outer profiled member so that the profiled members substantially areally rest at one another and form a capillary gap. An inner groove is cut over the length of the lock halves such that the inner groove extends through the wall of the inner profiled member into the wall of the outer profiled member. The area of the wall of the inner profiled member where the inner groove is located is sealed against the suspension with a sealing material introduced into the gap. The inner and outer profiled members are fused with a fusing material introduced into the inner groove. In an alternative embodiment a receiving groove is provided in the wall of the inner or outer profiled member such that the area where the inner groove is located is sealed by a sealing material introduced into the receiving groove.