Introduction of soft foundation treatment construction technology?

When it comes to the construction technology of soft foundation treatment, the relevant architects are still relatively unfamiliar. What is the basic situation of subgrade soft foundation treatment in China at this stage? What is the construction technology of grouting method to treat soft foundation? The following is the basic content of Zhong Da Consulting in combing soft foundation treatment for builders. The details are as follows:

Through combing the relevant contents, Zhong Da Consulting has made the following basic provisions on subgrade soft foundation treatment:

Before the building, if the foundation is not firm enough, in order to prevent the building instability and other accidents caused by the settlement and cracking of the foundation after the building, it is necessary to treat the soft foundation to make its settlement firm enough, improve the consolidation degree and stability of the soft foundation and make it meet the design requirements. This process is called soft foundation treatment, also known as soft foundation treatment.

Construction technology of soft foundation treatment;

(1) drilling

Grouting hole construction is the first process of grouting. For shallow soft soil, spiral drilling rig can be used, and for deep soft soil, rotary drilling rig should be used. In order to prevent bleeding, the aperture should be smaller, generally 75- 1 10mm, and the vertical deviation is less than 1%.

(2) pulping

According to the material test to determine the proportion, choose pulping materials, pulping should pay attention to the following points:

(1) Feed according to the procedure, accurately measure, master the slurry performance, and mix as much slurry as possible.

(2) The slurry should be fully stirred, and kept stirring before grouting, so as to prevent re-precipitation and affect the quality of slurry.

(3) Grouting

Grouting means injecting slurry into the target layer through grouting equipment and slurry pipeline. Grouting methods used in highway soft soil treatment projects include:

(1) Bottom-up orifice sealing grouting method. In this process, the hole formation is completed at one time, the orifice is closed with a triangular wedge-shaped slurry stopper, and grouting is carried out in sections from bottom to top, and the height of grouting section is between1.5-2.0m. This method is more suitable for soft soil layer with more cohesive soil layer or a small amount of medium-coarse sand layer in the lower part of the stratum.

② Top-down orifice sealing grouting method. This method only drills one grouting hole at a time, seals the hole with a triangular wedge grouting plug, and performs grouting in stages from top to bottom, and the grouting section is between1.5-2.0m. This method is more suitable for soft soil with more coarse sand layers in the middle and upper part of the stratum.

Before grouting, field grouting test should be conducted to determine the grouting quantity of single hole, and then construction should be carried out according to the grouting technology adopted. The side curtain hole shall be constructed first, then the reinforcement hole shall be constructed. Sequential construction shall be adopted, that is, 1 sequential hole shall be injected first, then the second sequential hole and then the third sequential hole. When the grouting quantity meets the design requirements, grouting can be terminated. The hole spacing of edge curtain holes should be 1/2 of that of general grouting holes to ensure the grouting quality.

After the construction of the side curtain hole, whether to construct the drainage hole should be determined according to the hydrogeological conditions of the treatment section. In the area with high groundwater level, a drilling rig should be used to drill 1-3 drainage holes within the control range, in order to discharge the groundwater within the range surrounded by the curtain holes at the edge with the grouting construction, so as to ensure the grouting quality more effectively. When grouting holes around the drainage holes are constructed and grouting slurry is seen in the drainage holes, the drainage holes can be filled with grouting slurry and sealed.

During grouting, when the ground swells or there is slurry leakage on the ground, grouting should be stopped and the reasons should be analyzed. The grouting quantity should be reduced in the next grouting section, and the hole sealing device and grouting equipment should be checked. If there is still uplift or slurry leakage on the ground, the grouting construction of the hole should be ended.

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