1, triaxial soil-cement mixing pile construction should be according to the geological conditions and the surrounding environment, the depth of pile, pile diameter, choose a different form and power of three-axis mixing pile machine, performance parameters of the supporting pile frame should match the blender pile depth, drill pipe and the agitating vane structure should satisfy the cement fully mixing in the process of pile and soil.
2, The three-axis pile stirring machine shall comply with the following provisions:
(1) The agitation drive motor shall have the function of displaying the working current;
(2) The pile frame shall have the function of adjusting perpendicularity;
(3) The main winch shall have stepless speed regulation function;
(4) Motor driven main winch should display motor working current, hydraulic driven main winch should display oil pressure;
(5(the stirring shaft at the lower part of the pile frame column shall be equipped with a positioning and guiding device;
(6)Stirring depth exceeding20m, the device shall be installed on the column guide rack in the middle of the stirring shaft.
3The working flow of the grouting pump should be adjustable, and the rated working pressure should not be suitableLess than2.5MPa, should be equipped with metering device.
Second,SMWmethodPreparation of construction methods
1Before the implementation of foundation pit engineering, the nature, use, scale, construction period, safety and environmental protection requirements of the project should be mastered, and the construction organization design should be prepared in combination with the construction conditions, geological conditions and surrounding environmental conditions obtained from the investigation.
2Before the construction of soil-cement mixing pile, it is necessary to investigate in detail the transportation routes of mechanical equipment and materials, construction site, operation space, underground obstacles, and the geological conditions that affect the quality and construction safety of soil-cement mixing pile (including stratum composition, soil, groundwater, etc.).
3The construction site should be leveled first, and the surface hard objects and underground obstacles in the construction area of the mixing pile should be removed. Under adverse geological conditions, the soil should be pumped, dredged, backfilled and layered and compacted. The bearing capacity of the road on site should meet the requirements of the piler and crane to move smoothly.
4Before the construction of cement and soil mixing pile, measurement and lofting should be carried out according to the position layout of mixing pile, and check and acceptance. According to the determined construction sequence, arrange the placement of steel, supporting machinery, cement and other materials.
5According to the axis of the steel soil-cement mixing wall, the guide groove is excavated, and the stirring pile positioning steel is set on the groove side, and the insertion position of stirring pile and steel is marked on the positioning steel.
6If cast-in-place reinforced concrete guide wall is used, the guide wall should be on the compacted soil layer, higher than the ground100mm, the net distance of the guide wall should be wider than the designed diameter of soil-cement mixing pile40mm ～60mm.
7, the mixing pile machine and slurry feeding system should be assembled and debugging in advance, and the construction of cement-soil mixing pile can be started after the test operation is normal.
8Before construction, the process parameters such as mixing sinking and lifting speed, cement slurry water-cement ratio and pile forming process should be determined through pile test; Time of slurry from conveying pipe to nozzle of mixer was measured. When the local water is erosive, suitable cement should be selected by test.
9Section steel positioning guide frame and vertical positioning suspension members shall be made according to the specifications and dimensions of the insert steel.
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