A construction structure for an underground facility, the construction structure comprising:
- a facility body including a foundation constructed by pouring concrete, and a cover member extending in a front-back direction and having both ends configured to extend downward and be fixed to a top surface of the foundation to form a tunnel-shaped space therebelow;
- a soil cover layer formed to cover the facility body with soil;
- an elevator passage formed to extend from the cover member to a location above the soil cover layer;
- an elevator car fitted into an inside of the elevator passage to be selectively lifted and lowered;
- a lifting device provided in a machine room formed in an top portion of the elevator passage, connected to the elevator car, and configured to selectively lift and lower the elevator car;
- and
- a fall prevention means configured to, when an abnormality occurs in the elevator car, be operated and prevent the elevator car from falling,
- wherein the fall prevention means includes:
- rail members provided to extend vertically inside the elevator passage;
- a braking member coupled into a guide hole, formed in a circumferential surface of the elevator car, to be slidable inward or outward, and configured to, when pushed outward, be coupled with the rail members and generate frictional force;
- elastic members connected to the braking member, and configured to press the braking member inward;
- and
- a pressing mechanism provided on a bracket provided in the elevator car, and configured to press the braking member outward when the elevator car is lowered at an abnormal speed;
- wherein the braking member includes:
- a slide block coupled into the guide hole to be slidable inward or outward, and provided with an outer surface inclined upward to an outside;
- and
- a friction member coupled to an outer surface of the slide block to be slidable in a vertical direction, and configured to come into close contact with the rail members and exert a braking force;
- and
- wherein the pressing mechanism includes:
- a cam wheel coupled to the bracket to be rotatable in the vertical direction, and having a cam formed on a circumferential surface thereof;
- an extension bar extending inward from the circumferential surface of the cam wheel, and having a weight at an inner end thereof;
- a torsion spring provided on the cam wheel, and configured to elastically press the cam wheel so that the extension bar is rotated upward;
- and
- a ratchet rotatably coupled to the bracket, and configured to, when the cam wheel is rotated such that the extension bar is rotated upward, be caught on an inner end of the cam and perform fixation in order to prevent the cam wheel from being rotated in an opposite direction.