Application of double-wheel slotting machine

According to the geological conditions of generally high soil strength in the whole slotting construction range of the upper Shagou station and the lining requirements of the slotting depth of the continuous wall, the milling and grasping combined construction process is adopted, that is, the ordinary hydraulic grab slotting machine in the area that cannot be drilled, first use two-wheel milling slotting machine for construction, and then combine with the ordinary hydraulic grab slotting machine to construct a thicker clay layer. According to the analysis of the geological conditions of the Upper Shagou Station, the first-class sodium bentonite [21] is mixed with mixing water to form mud for the retaining wall of the tank. See Table 1 for performance indexes of slotted retaining wall slurry in different strata. After the construction of the underground continuous wall is completed, the bentonite slurry used will gradually reach the required slurry performance requirements before pouring concrete through circulation, and the sand will be removed by the sand filter in the mud circulation system of the double-wheel tip groove machine.
3.2 slot segment milling
According to the design length (5.0m, 5.8m) of the unit slot section of the upper Shagou station, the cutting construction is carried out, and the section is divided again at the corners and other positions according to the design principle. Before slotting, check and record the number of the slot section, the position and size of the dividing line, etc., and after the error is correct, skip excavation and slot section milling shall be carried out in strict accordance with the sequence of the first phase slot section and the second phase slot section. Phase groove section. The design value of the single-hole slotting size of the slotting machine used in this excavation is 3.08m. In order to improve the construction efficiency, the two ends of each slot section should be cut first, and the middle of the milling should be completed and met the design requirements. Before placing the milling machine into the guide rail wall, the outer edge of the milling tooth of the milling machine must be aligned with the measurement line of the groove section at the top of the guide rail wall so that the side of the milling tooth is parallel to the guide rail wall. Grind the guide wall of the continuous wall flat, then put the milling wheel vertically into the guide wall groove, and fix the guide frame of the milling machine with a hydraulic fixing frame to prevent the milling cutter frame from shifting during the milling process. The construction of the line slot and affect the straightness of the slot milling hole. In addition, in order to ensure the verticality of the slot and the construction quality, the control of the feed speed and feed should be strengthened according to the depth range of the guide frame, so as to avoid damage to the milling wheel on both sides due to the large difference in rock height. Uneven stress and deflection will affect the normal construction progress.
3.3 cleaning of joints between tank and wall section
In order to improve the anti-seepage capacity and bearing capacity of the underground continuous wall, the reverse circulation system of the milling machine should be used to remove the sediment and gravel at the bottom of the trench in time after the completion of the milling construction.. During the construction of tank washing, high-quality mud must be continuously pumped into the tank section according to the design requirements, and no excessive or intermittent slurry must be allowed. The mud level in the tank section must always be kept within ± 2cm of the design level to avoid hole collapse due to unqualified grouting. After the tank is cleaned, stop grouting and check the tank depth 13] and other indicators. The density of mud measured by this process is 1.10~1.15g/cm3, the viscosity is 20~23s, and the sand content is 4%, all of which meet the design requirements.