CN-121992790-A - Mixed material pumping and drill lifting cooperative control method in CFG pile construction

CN121992790ACN 121992790 ACN121992790 ACN 121992790ACN-121992790-A

Abstract

The invention relates to a method for cooperatively controlling mixture pumping and drilling in CFG pile construction, which comprises the following steps of site positioning and pore-forming preparation, pile position testing and drilling machine positioning in a powdery clay stratum construction area, drilling verticality calibration, pore-forming liquefaction prevention drilling control, drilling construction by adopting a small blade spiral drill rod, pore-forming stability control by improving drilling speed and monitoring drilling verticality and pore depth errors in real time, mixture preparation and parameter control, cfG mixture preparation and parameter control according to the proportion of about 1:1 of cement, fly ash and crushed stone, stirring station parameter dynamic adjustment according to air temperature and humidity in the construction process to prevent pipe blocking, pumping and drilling cooperation forming control, pumping mixture starting after drilling reaches a designed depth, and mixture pumping amount matching with drill rod lifting speed in the drilling process is controlled, so that the mixture is ensured to be continuously filled to form a complete pile body.

Inventors

XU BING
LIU GANG
ZHOU MIN
JIANG XIAOFENG
SHI ZENGWEI
LOU ZHIQIANG
ZHANG LU
FENG CHENGBO

Assignees

中电建十一局工程有限公司
中国水利水电第十一工程局有限公司

Dates

Publication Date: 20260508
Application Date: 20260319

Claims (10)

1. The cooperative control method for the pumping and drilling of the mixture in the construction of the CFG pile is characterized by comprising the following steps: S1, site positioning and pore-forming preparation Pile position testing is carried out in a construction area of the powdery clay stratum, a drilling machine is positioned, and the perpendicularity of the drilling machine is calibrated; s2, pore-forming liquefaction-preventing drilling control Adopting a small-blade spiral drill rod to carry out drilling construction, and controlling the hole forming stability by improving the drilling speed and monitoring the perpendicularity and the hole depth error of the drilling in real time, wherein a drill bit of the small-blade spiral drill rod adopts an open drill bit; s3, pore-forming construction sequence control Drilling operation is carried out by adopting a pile-separating jump mode or a regional construction mode so as to reduce the sheeting liquefaction risk of the powdery clay stratum, and the number of piles formed every day is controlled in the construction process so that the number of piles does not exceed the regional bearing capacity limit every day, and the formation of a sheeting liquefaction region is prevented; S4, preparing mixture and controlling parameters Preparing a CFG mixture according to the proportion of about 1:1:1 of cement, fly ash and crushed stone, controlling the slump of the mixture to be 160-220mm, and dynamically adjusting parameters of a stirring station according to air temperature and humidity in the construction process to prevent a pipe from being blocked; s5, controlling pile formation by cooperation of pumping and lifting drilling After the drilling reaches the designed depth, starting to pump the mixture, controlling the pumping quantity of the mixture to be matched with the lifting speed of the drill rod in the drilling lifting process, and controlling the drill bit to be always buried in the poured mixture to a preset depth of about 3.0m so as to ensure that the mixture is continuously filled to form a complete pile body; the construction process is provided with a dynamic operation protection system, the dynamic operation protection system comprises CFG pile distribution and an informatization monitoring system, the CFG pile distribution mode adopts square full-hall arrangement, the adjacent pile distance of the CFG piles is 1.4-2.0m, the informatization monitoring system detects the pore-forming depth, the position deviation (< 2 cm) and the mixed material pouring quantity in real time, and the informatization monitoring system uses a level gauge and a distribution box system to track system data.
2. The method for controlling the pump and drill in cooperation with the CFG pile construction according to claim 1, wherein in step S2, the drilling rate is controlled to be greater than 20% of the conventional drilling rate in the liquefiable soil layer.
3. The method for controlling the pump and drill in cooperation with the CFG pile according to claim 1, wherein in step S2, the error of the hole forming depth and the deviation of the perpendicularity of the drilled hole are monitored in real time during the drilling process, wherein the error of the hole forming depth is controlled to be less than or equal to 0.1m, and the deviation of the perpendicularity of the drilled hole is controlled to be less than 1%.
4. The method for controlling the pump and drill lifting of the mixture in the construction of the CFG pile according to claim 1, wherein in the step S2, the perpendicularity of the drill rod of the drilling machine is calibrated through the theodolite after the drilling machine is positioned, and the construction is performed by combining drainage measures when the saturated pink layer is encountered, so that the stability of the hole forming is improved.
5. The method for controlling the pump and drill lifting of the mixture in construction of the CFG pile according to claim 1, wherein in step S5, the pump frequency of the mixture of each CFG pile is recorded during the pump construction of the mixture.
6. The method for controlling the pumping and drilling of the mixture in the construction of the CFG pile according to claim 1, wherein in the step S4, the slump of the mixture is adjusted to the upper limit of the slump range in a high-temperature construction environment, and the slump of the mixture is checked by a slump measuring cylinder.
7. The method for controlling the pump and drill extraction of the mixture in the construction of the CFG pile according to claim 1, wherein in the step S3, the number of the CFG piles formed per day is controlled not to exceed the number of the constructions allowed by the bearing capacity of the stratum in the construction process, and the length of the protection piles is set.
8. The method for cooperatively controlling the pumping and the lifting of the mixture in the construction of the CFG pile according to claim 1, wherein after the step S5, a mattress layer is arranged after the construction of the CFG pile is completed, the tamping degree of the mattress layer is controlled to be more than or equal to 0.9, the bearing capacity of the composite foundation is detected through a static load test, the detection quantity is not less than 1% of the total number of the CFG piles, and the bearing capacity of the composite foundation is not less than 520kPa.
9. The method for controlling the pump and drill in cooperation with the CFG pile according to claim 1, wherein in step S2, when the construction stratum is a saturated silt layer, water drainage measures are provided in the drilling construction area to improve the stability of the hole formation.
10. The method for controlling the pump and drill extraction of the mixture in the construction of the CFG pile according to claim 1, wherein in the step S5, the pile head is maintained after the injection of the mixture of the CFG pile is completed, so as to promote the strength development of the pile body.

Description

Mixed material pumping and drill lifting cooperative control method in CFG pile construction Technical Field The invention belongs to the technical field of foundation construction treatment, and particularly relates to a cooperative control method for pumping and lifting drill of a mixture in CFG pile construction. Background The CFG pile (cement fly ash gravel pile) composite foundation technology is a common foundation treatment mode, and a pile body structure formed by cement, fly ash, broken stone or stone dust and other materials is formed in foundation soil, so that a composite stress system is formed by the pile body, soil among piles and a mattress layer together, the bearing capacity of the foundation is improved, and the settlement of the foundation is controlled; compared with the traditional sand stone pile or gravel pile technology, the CFG pile can remarkably improve the strength and the overall stability of the pile body by adding cementing materials such as cement and fly ash, meanwhile, construction equipment is relatively simple, construction efficiency is higher, the CFG pile is widely applied to foundation treatment such as residential buildings, municipal roads, industrial plants and large-scale site engineering, in engineering practice, the CFG pile composite foundation not only can improve the bearing performance of a soft foundation, but also can reduce foundation deformation to a certain extent and improve the overall stability of the foundation, and therefore, the CFG pile composite foundation has important engineering application value in foundation treatment of soft soil, powdery clay and partial liquefiable stratum. However, when the CFG pile is constructed under the condition of a powdery clay stratum, the stratum soil body has the characteristics of high water content, high compressibility, low shear strength, poor permeability and the like, the conditions of insufficient hole wall stability, hole wall collapse or large local soil disturbance easily occur in the drilling construction process, and the phenomenon of liquefaction or plastic flow can even occur in partial areas, so that the pore-forming quality is influenced and the construction risk is increased; on this basis, the pumping and pouring of the mixture in the construction process of the CFG pile are usually required to be carried out synchronously with the drilling rod drilling lifting process, if the pumping quantity and the drilling lifting speed are controlled unreasonably, quality problems such as cavities, segregation or broken piles and the like can be caused in the pile body, and further the integrity of the pile body and the bearing capacity of the composite foundation are affected. Therefore, there is a need for a collaborative control method for pumping and drilling of a mixture in construction of a CFG pile, which reasonably controls links such as pore-forming operation, mixture pouring, construction organization and the like in the construction process of the CFG pile so as to improve pore-forming stability, and solves the problems of poor pore-forming stability, difficult guarantee of pile continuity and insufficient stability of construction quality existing in the construction process of the existing CFG pile. Disclosure of Invention In view of the above, the invention provides a cooperative control method for mixture pumping and drill lifting in CFG pile construction, which is applied to the technical field of foundation construction treatment and solves the technical problems of poor pore-forming stability, difficult pile continuity guarantee and insufficient construction quality stability in the existing CFG pile construction process. In order to achieve the technical purpose, the invention adopts the following specific technical scheme: A method for cooperatively controlling mixture pumping and drill lifting in CFG pile construction comprises the following steps: S1, site positioning and pore-forming preparation Pile position testing is carried out in a construction area of the powdery clay stratum, a drilling machine is positioned, and the perpendicularity of the drilling machine is calibrated; s2, pore-forming liquefaction-preventing drilling control Drilling construction is carried out by adopting a small-blade spiral drill rod, the drilling stability is controlled by improving the drilling speed and monitoring the perpendicularity and the hole depth error of the drilling in real time, and a drill bit of the small-blade spiral drill rod adopts an open drill bit; s3, pore-forming construction sequence control Drilling operation is carried out by adopting a pile-separating jump mode or a regional construction mode so as to reduce the sheeting liquefaction risk of the powdery clay stratum, and the number of piles formed every day is controlled in the construction process so that the number of piles does not exceed the regional bearing capacity limit every day, and the formation of a sheeting liqu