The entrance of the cave shall meet the following requirements when taking measures such as setting protective railings, stamping parts, hanging safety nets and installing gates according to specific conditions:
A, floor, roof and platform surface short side size less than 25cm but greater than 2.5 cm of the orifice, must be covered with a solid cover. The cover plate should be prevented from moving and shifting.
Second, the place such as the floor with a side length of 25 ~ 50 cm, the hole when installing prefabricated components and the hole temporarily formed due to lack of parts can be covered with bamboo and wood as the cover plate. The cover plate should be able to maintain the balance of surrounding laying, and measures should be taken to fix its position.
Three, the mouth of the cave with a side length of 50 ~ 150 cm, must be set with fasteners to fasten the steel pipe grid, and spread bamboo basketry or scaffolding on it. A protective net can also be formed by reinforced concrete slabs, and the spacing between the steel meshes shall not be greater than 20cm.
Four, the side length of more than 150cm hole, protective railings should be set around, and a safety flat screen should be set below the hole.
Five, garbage shaft and flue, should be with the floor masonry or installation and eliminate the hole, or refer to the reserved hole for protection. In the pipeline well construction, in addition to the above procedures, obvious signs should be added. If there is any temporary demolition, it must be approved by the person in charge of construction, and the protective facilities must be restored after the work.
Six, located in the hole next to the roadway, deep ditch and pipeline pit, groove, cover plate should be able to bear the load of not less than 2 times the effective bearing capacity of the local rated truck rear wheel.
Seven, the place such as metope vertical hole, the hole on the ground should be equipped with switch, tool or fixed protective door, door grid spacing should not be greater than 15cm, also can use protective railings, under the foot.
Eight, the bottom is less than 80cm from the floor or window sill and other vertical holes, if the edge drop is more than 2m, temporary guardrail with a height of 1.2 m should be added.
Nine, other vertical holes and holes that are dangerous to people and things falling nearby should be covered or protected, and measures should be taken to fix their positions.