Views: 0 Author: Site Editor Publish Time: 2026-04-28 Origin: Site
In the construction of various pile foundation projects such as high-speed rail bridges, building foundations, and municipal rail transit, the drilling quality and efficiency of rotary drilling machines directly determine the project construction period, the compliance rate of pile foundation bearing capacity, and the overall construction cost. The geological conditions in different construction areas vary greatly, and the distribution of soft soil silt layer, sandy pebble layer, weathered rock layer, hard rock and karst complex layer is different. The traditional single solidification drilling technology is prone to a series of construction problems, such as drilling jam, hole wall collapse, excessive sediment, serious wear of drilling tools, etc. With the continuous improvement of quality and efficiency requirements for infrastructure projects, refined construction, standardized drilling, and cost reduction operation and maintenance have become the core requirements for pile foundation construction. Optimizing the drilling process of rotary drilling rigs based on different geological conditions, matching exclusive drilling parameters, drilling tool selection, and construction supporting measures, is the core key to ensuring stable drilling quality, continuously improving drilling construction efficiency, and reducing rework losses.
Current situation of pile foundation construction industry: complex and variable geology forces iterative optimization of drilling technology
The current domestic infrastructure pile foundation construction site covers a wide range, with complex and diverse terrain, landforms, and geological structures. Most construction sites are not single homogeneous geology, but multi-layered composite geology alternately distributed, with significant differences in hardness, compactness, and permeability between the upper and lower strata. Traditional rotary drilling rig construction often relies on the experience of operators to set drilling speed, torque, and footage speed, with inconsistent process standards and high operational flexibility. In soft soil layers, problems such as over drilling, diameter reduction, and hole wall disturbance and collapse are prone to occur. In sand and gravel formations, problems such as slurry leakage, hole collapse, and difficult slag discharge are prone to occur. In hard rock formations, problems such as slow drilling, drill tooth collapse, and stuck and buried drilling occur frequently. Insufficient process adaptability not only significantly reduces overall drilling efficiency, but also easily leads to quality defects such as deviation in borehole verticality and excessive sediment thickness. Subsequent rework and rectification are time-consuming and labor-intensive, with additional construction consumables, equipment maintenance, and labor costs, seriously restricting the timely and high-quality delivery of pile foundation projects. The industry urgently needs to implement specialized geological drilling process optimization plans.
Optimization of Technology for Soft Soil and Muddy Strata: Stability of Hole and Wall Protection as the Main Approach, Constant and Slow Progress to Reduce Disturbance
Soft soil and silty soil are geological conditions with soft soil, high moisture content, loose soil structure, and weak pressure bearing capacity. When drilling with a rotary drilling rig, problems such as hole wall shrinkage, hole collapse, and excessive disturbance at the bottom of the hole are most likely to occur. The core focus of construction is to stabilize the hole wall, reduce soil disturbance, and ensure smooth soil discharge. In the process of process optimization, it is necessary to abandon the habit of rapid and aggressive construction, and adopt a drilling mode of low speed, low torque, and constant speed and slow progress. The depth of each drilling step should be strictly controlled to prevent excessive disturbance of the surrounding soil caused by one-time downward pressure of the drill rod. Synchronize the optimization of mud ratio parameters, appropriately increase the mud colloid rate and viscosity, enhance the pressure bearing capacity of mud wall protection, form a dense mud skin on the surface of the hole wall, block groundwater infiltration, and prevent hole wall collapse from the source.
The selection of drilling tools is suitable for the double bottom lightweight sand scoop, which utilizes shallow depth rapid drilling and soil removal methods to reduce the time the drilling bucket stays in the hole and avoid long-term operation that disturbs the soil of the hole wall. Slow down the lifting and lowering speed during the drilling process to avoid the problem of negative pressure suction and collapse of the hole wall caused by rapid lifting. During the drilling process, the water head inside the hole should be continuously maintained at a stable height, and timely slurry and water replenishment should be carried out to maintain pressure balance inside the hole. By optimizing and adjusting the entire process, it is possible to ensure the regularity of drilling in soft soil layers, prevent the rework of shrinkage and collapse holes, and steadily improve the efficiency of continuous drilling under stable construction conditions, reducing downtime for troubleshooting and rectification.
Optimization of permeable formation technology for sand and gravel: strengthening mud wall protection, strictly controlling key links for preventing collapse and leakage
The sand and gravel formation has loose particles, high porosity, and strong permeability, making it a complex formation with high difficulty in forming holes in pile foundation construction. Construction is prone to problems such as mud leakage, unstable hole walls, collapse of holes, and difficulty in cleaning up gravel sediment. The drilling efficiency is consistently low, and the construction failure rate is high. The core of process optimization in this geological condition focuses on strengthening wall protection and leakage prevention, efficient slag discharge, and smooth drilling, completely changing the shortcomings of traditional construction with insufficient mud concentration and chaotic drilling rhythm. In the early stage of construction, special wall protection slurry with high density, high viscosity and high stability shall be prepared in advance, and anti-seepage additives shall be added if necessary to block the pores of the sand layer, effectively prevent mud loss and groundwater backflow, and build a stable foundation for the hole wall.
The drilling operation adopts intermittent graded drilling technology, with segmented drilling, segmented slag discharge, and segmented wall protection, to avoid long-term continuous drilling causing stress imbalance on the hole wall. Select reinforced louver sand scoop with anti slip drilling teeth to enhance the ability to grab and discharge pebbles, and reduce drilling resistance caused by the accumulation of pebbles at the bottom of the hole. Strictly control the drilling speed and pressure, and prevent blind pressure from causing drill pipe shaking, hole wall collision and damage. In the later stage of borehole formation, a secondary cleaning process will be added to thoroughly clean the sand and gravel accumulated at the bottom of the borehole, ensuring that the sediment thickness meets the standard. Through targeted process optimization, the stubborn problem of slurry leakage in sand and gravel formations is effectively solved, reducing the number of construction delays and rework, and significantly improving the qualification rate of single hole drilling and overall drilling construction efficiency.
Process optimization of weathered rock formations: dynamic parameter adaptation, smooth transition of soft and hard alternation drilling
Fully weathered, strongly weathered, and moderately weathered rock layers are common composite strata in infrastructure construction. The rock layers have alternating distribution of soft and hard layers, uneven weathering degree, and many interlayers. During the drilling process, problems such as drilling rig shaking, drill rod deviation, large deviation in borehole verticality, and intermittent drilling speed are prone to occur, which not only affect the quality of borehole formation but also restrict the overall construction progress. The core of optimizing the formation process lies in dynamically adjusting drilling parameters, switching torque, speed, and pressure modes in real time according to the weathering hardness of the rock layer, achieving smooth transition drilling in soft and hard formations, and avoiding construction failures caused by constant parameters.
When entering the soft weathering layer, moderately increase the rotational speed, reduce the pressure, and quickly advance the drilling operation; When encountering hard weathered interlayers, immediately reduce the speed and increase the output torque, slowly grind at low speed to steadily break the rock, and prevent high-speed hard drilling from causing drill tooth damage and drill pipe deformation. Equipped with a cutting tooth drill bucket that is suitable for the type of rock formation, replace worn drill teeth in a timely manner according to the hardness of the rock formation to avoid blunting and slowing down the drilling rhythm. Real time monitoring of hole verticality during the construction process, timely adjustment of drill rod posture in case of deviation, and early avoidance of later correction and rework. By dynamically adapting parameters and adjusting processes in real-time, continuous and stable drilling of weathered rock layers can be achieved, balancing drilling accuracy and speed, effectively improving overall construction efficiency.
Optimization of process for complex hard rock formations: low to high twist rock breaking, graded crushing to reduce equipment losses
Hard rock formations have high rock strength, dense structure, and high hardness, making it extremely difficult for rotary drilling rigs to break rocks. Traditional conventional drilling techniques not only have extremely slow drilling speeds, but also easily cause problems such as rapid wear of drill teeth, deformation of drill rods under stress, and damage to hydraulic systems due to overload. The equipment maintenance costs are high and the construction period is long. The core of the optimization of hard rock formation technology adheres to the construction principles of low speed, high torque, graded crushing, and gradual progress, abandoning the extensive construction mode of blindly pressing hard drilling, and aiming to reduce equipment loss and improve rock breaking efficiency as the primary goal.
Maintain low-speed operation throughout the drilling operation, relying on the high torque output of the drilling rig to slowly grind and break rocks. It is strictly prohibited to forcefully drill at high speeds that may cause equipment load surges. Choose toothed rolling cutters or specialized rock breaking drilling tools to enhance the ability to break hard rocks. Adopt a layered and graded crushing method, with reasonable control of the depth of each rock breaking operation to avoid drilling jamming and burying caused by excessive single footage. Timely check the wear of drilling tools during construction intervals, regularly replace damaged drill teeth, and avoid continuous inefficient operation after drilling tool wear. Synchronize and optimize the operation and maintenance of equipment hydraulic systems to ensure stable power output and reduce equipment downtime due to malfunctions. Through process optimization, hard rock drilling operations can be completed quickly and efficiently, while reducing equipment failure rates and the cost of replacing vulnerable parts, achieving a balance between improving quality and efficiency while reducing costs in operation and maintenance.
General supporting construction optimization: full process control ensures continuous improvement of drilling efficiency
In addition to optimizing the drilling process for geological specialties, the management of the entire construction process and the optimization of equipment operation and maintenance are important foundations for ensuring the long-term improvement of the drilling efficiency of rotary drilling rigs. Carry out geological survey and disclosure work in the early stage of construction, accurately grasp the distribution of geological strata at the construction site, plan and adapt drilling tool types and drilling process parameters in advance, and avoid blind construction operations. Standardize the operation process of construction personnel, eliminate illegal operations, rough drilling and other behaviors, unify and standardize construction techniques, and reduce efficiency losses caused by human operational errors. Establish a daily maintenance ledger for equipment, regularly inspect the status of drill rods, hydraulic systems, and vulnerable parts of drill buckets, and carry out maintenance and replacement work in advance to avoid equipment failure and downtime.
Reasonably connect the drilling, hole cleaning, steel cage hoisting, and concrete pouring processes, reduce waiting time for process connection, and achieve seamless construction connection. Relying on intelligent construction monitoring equipment, real-time monitoring of core data such as drilling depth, verticality, torque and speed, timely adjustment of construction technology, and early prediction of construction hazards. Through comprehensive and full process optimization, combined with specialized geological process adjustments, a complete and efficient construction system for rotary drilling rig drilling has been formed, fundamentally improving the overall progress and quality of pile foundation construction.
