The main causes of elevator shaft leakage

(1) Due to the waterproofing layer being applied to the bottom plate first, the concrete wall on the side wall of the elevator shaft was reconstructed, resulting in a fault between the concrete wall on the side wall and the bottom plate. The original construction waterproof layer did not have the expected waterproof effect, so groundwater will continuously leak into the elevator shaft from the fault.

(2) During civil construction, a large amount of accumulated water on the bottom plate was not completely drained, and the concrete was directly poured into the water, resulting in many honeycombs, pits, holes, and looseness around the bottom plate. The handover with the bottom plate is not tight, and the bottom of the elevator shaft is generally below the positive and negative zero water level line. When the groundwater pressure is high, groundwater will leak into the pit through holes, pits, cracks, and looseness, causing water accumulation in the elevator shaft.

(3) The inner and outer walls of the elevator shaft were not treated with waterproofing, causing groundwater to seep into the walls and cause water accumulation in the elevator shaft.

Maintenance methods

Clean up the grassroots

Firstly, drain the accumulated water in the elevator shaft foundation pit and mezzanine, and clean the base layer;

Cloth hole

Hole arrangement: the construction operator shall find the leakage points one by one from the first survey of the elevator shaft foundation pit, and mark them with red spray paint. The marking method is determined based on the different locations of leakage. Large areas of leakage are marked with dense red dots, and cracks are marked with red x, usually alternating on both sides every 250px along the direction of the crack. Individual water seepage points are marked with red ○;

Drilling construction

Drilling construction: After the drilling is completed, the following construction personnel hold an electric drill and drill at a 45 º angle with the base surface at 3 to 100px next to the leakage point, according to the red mark. The diameter of the grouting nozzle is 10mm, and the drilling depth is half of the thickness of the structural layer. The drilling depth of the hole marked with the red dot should be shallow, and the drilling depth of the point marked with the red x should be deeper and slightly inclined towards the crack. The drilling depth indicated by the red ○ should be deep until there is clear water flowing out; Then install the grouting nozzle at the location where the hole has been drilled, and try to set it as deep as possible, exposing only 1 to 37.5px outside the wall and tightening it.

Grouting construction

Grouting construction: The grouting is carried out using an electric grouting machine, and a pressure gauge is installed at one end of the grouting pipe. When the injection volume of each grouting hole is less than 5L/min and reaches the design pressure, it stabilizes for 10 minutes. When the water absorption rate of the inspection hole is less than 1.0L/min per meter, the grouting is completed, and then the next construction is carried out;

Sealing treatment

Sealing treatment: After grouting is completed, remove the grouting nozzle and seal it with rigid sealing material;

Brush coating

After grouting is completed, apply 4mm Jishitu 101 flexible waterproof mortar.