Cofferdam lead hole slotting and grouting construction method for deepwater hard rock steel plate pile

Abstract

The invention discloses a cofferdam lead hole slotting and grouting construction method for a deepwater hard rock steel plate pile. The cofferdam lead hole slotting and grouting construction method comprises the following steps of: 1) mounting a lead hole protective barrel guide frame; 2) separating and dropping a lead hole protective barrel according to the guide frame; 3) separating the lead hole and deslagging through a rotary excavating drilling rig and a barrel-shaped drill bit, and forming a notch in a mode of stacking circular holes; 4) pulling out a lead hole steel protective barrel, and dumping and filling soil in a lead hole slot; 5) splicing and dropping inner support for construction; 6) welding a grouting tube at the inner side of a bottom slot hole of the steel plate pile, and infiltrating the bottom of the steel plate pile to a slotting area; and 7) after a cofferdam is formed, pouring cement paste into a grouting tube for sealing a water permeable channel on the bottomof the cofferdam. The problem that stability of the steel plate pile is finally affected as a steel plate pile in hard rock cannot be infiltrated and the cofferdam is insufficient in integral embedding-fastening depth is solved by rotary excavating and lead hole slotting. The bottom water seepage problem of the cofferdam is solved by pile-bottom grouting, so that back-cover-free construction is possible.

Description

technical field [0001] The invention relates to the field of bridge construction, in particular to a construction method for slotting and grouting construction for deep-water hard rock steel sheet pile cofferdam lead holes. Background technique [0002] The construction of bridge caps requires the use of cofferdams to provide a dry environment for operations. In domestic deep-water hard rock geological conditions, underwater blasting of bedrock is generally adopted, and then the double-walled casing is used to float and transport to the place for construction. The main problems are as follows: [0003] 1. The lowering of the double-walled cofferdam requires underwater blasting of the bedrock. The processing of the cofferdam is difficult, and the construction requires a large amount of marine machinery and equipment, and it is difficult to recycle, with high cost and long construction period; [0004] 2. Double-wall steel cofferdams are used for construction, which requires a...

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Problems solved by technology

[0003] 1. The lowering of the double-walled cofferdam requires underwater blasting of the bedrock. The processing of the cofferdam is difficult, and the construction requires a large amount of marine machinery and equipment, and it is difficult to recycle, with high cost and long construction period;

[0004] 2. Double-wall steel cofferdams are used for construction, which requires a large thickness of bottom-sealing concrete to meet the stability requirements of the base after pumping (generally, the water depth increases by 2-3m, and the bottom-sealing concrete needs to be increased by 1m), which greatly increases the excavation of the foundation pit. depth, so that the cofferdam needs to be anchored deeper into the soil, and at the same time, the safety risk during the excavation of the foundation pit is multiplied;

[0005] 3. If the steel sheet pile cofferdam is used for construction, the hard rock cannot be driven in, and the depth of the steel sheet pile is not deep enough for construction;

[0006] 4. The introduction hole equipment capable of drilling into medium-weathered rock formations with a strength of 30MPa includes rotary drilling rigs, double-wheel slot milling machines, impact drills, and steel sheet pile pilers, but the cost and cost of double-wheel slot milling machines and steel sheet pile pilers Relatively high, the drilling efficiency of the impact drill is low and the effect is poor

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