September 8, 2022
Requirements for Construction Equipment of High-Pressure Jet Grouting Pile
The main high-pressure rotary spray construction tools include a drilling rig, high-pressure grouting pump, air compressor, mixer, drilling tools, etc. Among them, the air compressor is the standard configuration, with no special requirements.
In the rotary jet grouting construction, the drilling rig is mainly used to lift the drilling tool in the process of hole forming and rotary jet grouting, and the gyrator can drive the drill pipe to make 360. Rotary and can swing back and forth within a specific angle range, to achieve rotary spray, swing spray, and fixed spray three functions. The specific construction method must have special requirements for equipment. In the past, people made simple changes to the core and vibration drilling rig, but it was difficult to adapt to the requirements of rotary jet construction.
Drilling Rig
(1) The drilling rig must have sufficient torque, lifting force, and feed force, be able to quickly form holes, and have a certain ability to deal with accidents;
(2) The rig power head in addition to 360 ° rotation, also must be able to swing rotation within a certain angle range, to achieve rotary spray, swing spray, and fixed spray function;
(3) The drilling rig must have a long run, as far as possible to reduce the number of drill pipe screwing and unloading, reduce the number of pauses and pause time in the process of pile formation, so as not to affect the quality of pile formation;
(4) The power head rotation speed, feed speed, and lifting speed can be stepless adjustment within a certain range, micro precise adjustment and equipped with various instruments can correctly reflect the above parameters, improve the quality of pile;
(5) The column can be tilted within a certain range to ensure the requirements of jet grouting inclined hole, and the column tilt angle can be accurately controlled to ensure the correct pile position;
(6) Rotary jet grouting construction environment is relatively poor, requiring equipment must have high reliability, centralized operating position, easy to control, and easy maintenance;
(7) Equipment must have environmental protection, high efficiency, energy saving, and safety features;
(8) Jet grouting construction, single hole construction speed is faster, equipment relocation must be convenient and fast;
High-pressure grouting pump
A high-pressure grouting pump is the most critical equipment in high-pressure jet grouting. The pump absorbs slurry or water at low pressure, discharges it at high pressure through a nozzle, cuts and stirs soil, and forms a jet grouting pile. The pressure and flow of a high-pressure grouting pump directly affect the diameter of the pile and the quality of the pile. The requirements of the high-pressure grouting process for the pump are as follows;
(1) The pump pressure and flow can be adjusted within a certain range, preferably step-less adjustment, requiring the pump pressure to adapt to the nozzle diameter, pile diameter, and soil standard penetration value changes;
(2) pump pressure can be accurately displayed, and can automatically maintain the pressure in the set value range of continuous work, with an overpressure alarm, and automatic shutdown function;
(3) the flow count requires accurate, can accurately display the current flow and flow accumulation, by controlling the number of sprayed slurry pile quality control;
(4) High-pressure grouting pumps must have high reliability, safety, energy saving, and environmental protection;
Drilling Tools
In the rotary jet grouting construction, the drilling tool mainly plays the role of transmitting power and conveying slurry. The triple tube drilling tool is required to transport water, gas, and slurry at the same time without cross flow. It is composed of three parts: guide vane, triple tube drill pipe, and nozzle. The requirements of high-pressure jet grouting for triple pipe drilling tools are as follows:
(1) The drill must have sufficient strength, stiffness, and ability to transmit sufficient torque to ensure that the hole and easy to connect;
(2) Can simultaneously transport water, gas, and slurry three media without cross-flow, high-pressure sealing performance ;
(3) The drilling tool can transfer power in the process of clockwise and counterclockwise rotation to ensure the realization of the swing spray process;
(4) Inside and outside the two layers of nozzle ring gap uniform, nozzle geometry reasonable, smooth inner wall, wear-resistant and durable (generally made of carbide).
