How to Construct Cement Mixing Pile in Steel Silo

Cement mixing piles is based on physicochemical principles of cement reinforcement, during the mixing. Cement and soil are mixing more fully, the smaller the clod will be crushed, the more uniform distribution of cement, the smaller the dispersion of cement soil, thereby enhancing the strength of the foundation. Cement mixing pile is usually more suitable for silt, soft soil, and cement mixing piles and silt strata. Cement mixing piles construction is a important process of steel silo construction. 

Preparation Work

Cement mixing pile through a special deep mixing machinery, in the deep of soft soil, forced agitation of soft soil and cement, and then make the soft soil and cement form a hard and firm combination, to become a kind of cement with enough hardness and strong stability. Before the cement mixing pile construction, should clean up large stones, garbage, roots and other obstacles, leveling the ground. Especially the foundation with shallow groundwater, needs to drop the water level and then to remove mud and miscellaneous fill. At the same time should perform a thorough inspection of the equipment to ensure the mechanical properties in a normal good condition.

Checking the Pile Body & Foundation

After the construction preparation work, needs to start the test pile. The purpose of the test pile are determining the amount of cement, mixing times, pumping pressure, lifting speed and other parameters, which provides the basis for cement mixing pile construction. Choose cement materials, and use after inspection. Generally use PO42.5 cement, test pile number 5, the cement content of 13%, 14%, 15%, 16%, 17%. After the completion of 28d test pile, needs to test the strength of pile body and bearing capacity of foundation, determinate cement mixing pile construction parameters. Generally water-cement ratio is 0.5, the cement content is 14%, using four mixing and second shotcrete construction process.

Cement Mixing Pile Construction

Cement mixing pile construction process requires fixed the pile position according to the drawings. For the pile lofting, needs to check the performance of pile foundation debugging, make sure the mixer is in-position, then turn on the mixer, control the sinking speed and sank to design depth. In strict accordance with the design ratio of allocation of cement slurry before mixer drilling, after the mixer sank to a certain depth, pressed the slurry into soil and turn back, enhance the mixing speed of shotcrete. Repeat mixing after raise the mixer to a certain height. When a mixing pile construction is completed, injection clean water for cleaning, then shift to the next stirring pile construction. During the construction process, need to select the appropriate equipment, a detailed digital record of each cement pile is required and it’s necessary to send professional personnel to supervise cement stirring pile work. Configuration of cement slurry shall not stagnate for such a long time, shall not appear pulp phenomenon and strictly control the time of spraying and stopping slurry. When the pulp volume is insufficient, should be promptly in accordance with the design requirements of complex agitation spray.

Quality Testing Working of Mixing Pile

Quality testing is an indispensable link in cement mixing pile work. According to the regulations of the standard to test the pile spacing, pile length, bearing capacity of single pile, as well as spraying pile strength. Check whether there is any loose phenomenon, and the pile distance is uniform. After pile 28d, check the integrity and uniform length of the pile body. When the failure rate is less than 10%, then the cement mixing pile is meet the requirements. The rate between 10% -20% is equivalent to fill the pile. If it is greater than 30%, it is judged as non-conforming.

Cement mixing pile technology is a very effective technical method for dealing with weak foundation, not only can strengthen the weak foundation, but also improve the bearing capacity of the foundation. It is widely used in foundation treatment and has the characteristics of economical application. It also can reduce the project cost to a large extent.