In the CSM (dual-wheel milling soil-cement mixing wall) method, the conventional dual-wheel milling maximum power is 330& NBSP; KW, the maximum working pressure is 300  Bar can generally be applied in soft soil layer, sand layer and strong weathering rock, but it cannot be applied in the face of moderate weathering rock. If there is a project that requires the CSM to enter the middle weathering rock, there must be very few construction units and construction equipment to undertake this task. The third company of China Construction Bureau II encountered such a difficult problem in the CSM engineering of Block D of Nanjing Binjiang Headquarters Base No.2014G34 Project.
Details >Preparation and regulations for construction of reinforced composite piles
Before the construction of the reinforced composite pile, the pile forming process test shall be carried out, and the number shall not be less than 3. When the pile quality cannot meet the design requirements, it should be tested again after adjusting the parameters related to design and construction. The allowable deviation of each single pile position in the rigid composite pile should be 10mm soil, the allowable deviation of the vertical degree of the elastic composite pile should be 1%, and the allowable deviation of the vertical degree of the elastic composite pile, flexible and rigid composite pile and ternary composite pile should be 0.5%.
Details >Construction regulations and advantages of reinforced composite piles
According to the requirement of design pile diameter, cement-soil mixing pile is formed in the process of grouting. The prestressed concrete pipe pile implanted into the cement soil after mixing has the advantages of convenient construction and good economic benefits. It has the following advantages:
Details >SMW construction inspection and acceptance
The INSPECTION ITEMS AND technical INDEXES of raw materials such as cement and admixture used in SMW construction slurry mixing should meet the design requirements and relevant national standards. Check quantity: Check by batch. Inspection method: Check product certificate and retest report.
Details >SMW construction H - section steel insertion and removal method
The water-cement ratio is generally 1.8 when the SMW pile is inserted into the H-shaped steel. At the same time, it is required that the hanging bars should be set on the top of the H-shaped steel. When the H-shaped steel is inserted, it is placed on the positioning channel steel to control the top elevation of the H-shaped steel. When the section steel is in place and does not sink, it is not necessary to sling.
Details >SMW construction equipment 1, triaxial soil-cement mixing pile construction should according to the geological conditions and surrounding environment conditions, the depth of pile, pile diameter, choose a different form and power of the 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 and soil in the process of pile fully mixing.
Details >SMW construction quality assurance measures
1. Protection of pipelines in surrounding areas (1) Before construction, investigate the buried depth, path and surrounding distance of pipelines, especially large-caliber pressure pipelines, and set up monitoring points for real-time monitoring during the whole construction process. (2) When piping displacement alarm is given, effective measures should be taken immediately, such as controlling the construction speed of mixing pile and adjusting process parameters.
Details >Key points of SMW construction technology
Key points of SMW construction technology: 1. Strict control of design requirements for slurry preparation. 2, the soil should be fully stirred, the sinking speed should be strictly controlled, so that the original soil is fully broken to help evenly mix with cement slurry. At the same time, in order to accelerate and reduce the impact on the surrounding strata, the stirring can be connected with compressed air for full stirring.
Details >Brief introduction of SMW construction method
SMW construction method is to use multi - axis pile stirring machine in the project site one by one construction. The cement slurry or soil curing agent is spouted from the drill bit and mixed repeatedly with the foundation soil to form a continuous and complete underground wall with certain strength and stiffness without joints. Suitable for building foundation pit retaining wall, water curtain or soft foundation soil reinforcement.
Details >SMW is the abbreviation of the Soil Mixing Wall, which was introduced in Japan in 1976 and is now widely used in the open tunnel enclosure and deep foundation pit waterproof curtain. In this method, a multi-axis drilling mixer is used to drill at a certain depth on site, and the curing agent is sprayed at the bit to continuously mix and stir with the soil. Each pile body is constructed by lapping.
Details >Hong Kong airport is the biggest challenges facing the third runway construction aspect, before the project starts, sea DCM (mixing pile), land DCM (mixing pile), PVD (drain) in the sea, land gravel pile foundation treatment technology such as are for Japan, South Korea, the monopoly of international advanced technology, before and after the tender, the foreign counterparts enterprises of our country executes strict technology blockade. For this reason, the strong foundation has carried on the thorough research. After more than two years of continuous fighting day and night, countless scientific research, testing and adjustment, we have overcome the difficulties of equipment manufacturing and construction technology of PVD (drainage board) engineering ship, DCM (mixing pile) engineering ship, onshore gravel pile machine, and onshore DCM pile machine, and successfully mastered the core technology.