However, the content of the research is only stopping at the research and design of technology for machine manufacturing, without mentioning advanced research on the dynamics of the hydr
Trang 1UNIVERSITY OF TRANSPORT AND COMMUNICATIONS
-o0o -
NGUYEN THUY CHI
RESEARCH ON SCIENTIFIC BASIS TO DETERMINE REASONABLE TECHNICAL PARAMETERS OF BUCKET DRILLING MACHINES MADE IN VIETNAM
Major: DYNAMIC MECHANICAL ENGINEERING
Code: 9520116
SUMMARY ENGINEERING DOCTORAL THESIS
Hanoi - 2021
Trang 2Thesis completed at:
At , date month year 20
This thesis may be learnt at:
1 Library of University of Transport and Communications
2 National Library of Vietnam
Trang 3INTRODUCTION
1 Urgency of the thesis
Currently, there are many different equipment used in the construction of foundations and foundations of construction works, including bored pile drilling machine Types of bored pile drilling machines being used in Vietnam are imported from abroad with expensive prices and the most difficult thing in
"localization" the product is to manufacture the working set of the machine Starting from that, the production units are looking for ways to research and calculate the design of the machine's working set to replace imported equipment However, the content of the research is only stopping at the research and design
of technology for machine manufacturing, without mentioning advanced research
on the dynamics of the hydraulic transmission system and optimal design for bored pile drilling machine In addition, this is specialized equipment, so it is not easy, requiring basic research, scientific basis and especially technological know-how in manufacturing suitable mechanical products with the current level of technology in our country Therefore, the topic "Research on scientific basis to determine reasonable technical parameters of bucket drilling machines made in Vietnam" is topical and highly urgent
2 Objective of the thesis
The research determines the reasonable technical parameters (structural and working parameters) of the bucket drilling machine made in Vietnam mounted
on crawler cranes Based on the obtained research results, the thesis recommends some reasonable technical parameters of the machine in mining conditions in the Northern Delta
3 Object and scope of research
m, working in the Northern Delta
4 Research content
- Overview of research issues
Trang 4- Research on hydraulic drive system dynamics of bucket drilling machine made in Vietnam
- Research to determine structural parameters and reasonable working parameters of drill buckets
- Experimental research to determine the dynamic parameters of the Hitachi CX500 bored pile drilling machine
5 Scientific and practical significance of the thesis
a Scientific significance:
- Building a dynamic model of the hydraulic motor driving the drill plate and the dynamics of the hydraulic cylinder system of the drill plate of a rotary bucket-type bored pile drill mounted on a crawler crane in Vietnam corresponding to the following states: machine work
- Building a simulation program of bored pile drilling machine in typical working cases, surveying the factors affecting the dynamic characteristics of the machine and then recommending reasonable technical parameters of the bored pile drilling machine from the point of view of dynamics
- Building and solve the optimization problem according to the minimum specific energy cost criterion, thereby determining the reasonable structural and working parameters of the bucket
b Practical significance:
- The research results of the thesis can help manufacturers or operators of bored pile drilling machines as a reference in the design and manufacture of a working set of machines with high economic and technical criteria and use to select and operate equipment with reasonable working parameters
6 New points of the thesis
- Building and solving the dynamic model of the hydraulic motor driving the drill plate and the hydraulic cylinder pressing the drill plate on the bucket drilling machines during construction in the Northern Delta of Vietnam
- Surveying the factors affecting the dynamic characteristics of the hydraulic transmission system of the machine and then recommending reasonable technical parameters (structural and working parameters) of the bucket drilling machines from the point of view of dynamics
- Setting up and solving the optimization problem of structural parameters and working parameters of the bucket according to the minimum specific energy cost
Trang 5CHAPTER 1: OVERVIEW OF RESEARCH ISSUES
1.1 Introduction of Hitachi CX500 crawler crane mounted rotary bucket bored pile drill
a General introduction
The Hitachi CX500 crawler crane-mounted rotary bored pile drill is a drilling machine in which the rotating bucket-type operator is mounted on the base machine of Hitachi's crawler crane This is a drilling machine made in Japan
in 1995, with a kelly rod-type drill rod, considered a high-yield device, able to drill from soft to hard geological strata such as sand, clay, gravel etc The biggest advantage is that it can drill holes up to 70 m deep, up to 2000 mm in diameter with a travel velocity of 1.7 km/h, providing high efficiency during construction The machine structure is quite simple, the user can easily control and operate it during the working process Although the initial investment cost for the machine
is quite expensive, the work efficiency increases many times compared to other types of machines
The machine's size is compact, moving and changing the working position
is quick and convenient, in addition, it can also self-service lifting equipment and supplies during the working process Due to the crawler moving unit, large contact surface on the ground surface, the CX500 boring machine can move easily on soft ground, suitable for construction site terrain with many rough and sharp obstacles
Figure 1.2 Bucket drilling machine mounted on Hitachi CX500 crawler crane 1- CX500 base machine; 2- Kelly bar; 3- Drill plate holder 4- Drill plate;
Trang 6The work set of bucket drilling machine mounted on Hitachi CX500 crawler crane includes: ED12 drill head assembly (including: drill plate, drill drive motor, planetary reducer, drill plate feed cylinder, etc.), kelly rod and drill bucket PhD candidate selects the type of working bucket as a rotating bucket because the rotating bucket can be easily manufactured in the country, suitable for the technological conditions and skill level of our country's workers, in addition, it is possible to purchase other details or assemblies that cannot be manufactured domestically Currently, there are many types of standard rotating buckets, depending on the requirements and nature of the work, people choose different types of drill buckets with different diameters
The rotating bucket has a structural feature that is different from other types
in that at each point on the cutter edge, it performs a reciprocating motion in the direction of going deep into the ground and combining the rotational movement
at the same time During the deformation and destruction of rock, the movement
of the soil shavings is separated and slides on the top surface of the bucket teeth and accumulates in the bucket At the time of drilling, each point on the bucket teeth performs a reciprocating motion in the downward direction and a rotational motion The amount of longitudinal feed of the bucket during drilling will depend
on the bucket pressure from the top as well as the compressive strength of the rock, [34], [36] The torque from the drill rod transmitted to the bucket causes the bucket to rotate Structure of the rotating bucket is as shown in Figure 1.4 below:
Figure 1.4 Structure of rotating bucket of bored pile drilling machine 1- Positioning nose; 2- Bucket wall; 3- Bucket bottom open handle; 4- End on drill bucket; 5- Top of drill bucket; 6- Strengthening tendon;
7- Bucket bottom hinge; 8- Bucket teeth
1.2 Overview of research works at home and abroad related to the thesis 1.2.1 Overview of studies on the dynamics of bored pile drilling machines
There have been many works by scientists in China, Vietnam and other countries researching the dynamics of bored pile drilling machines, which have been presented in the documents [47], [63], [67] From these studies, it can be
According to A
Trang 7seen that, the works mainly focus on the research on the dynamics of the guide ring as well as the simulation of the dynamics of the guide rack structure of the bored pile drill while the dynamics The hydraulic drive system of the machine is not taken into account
1.2.2 Overview of research works on structural optimization analysis of bored pile drilling machines
In the world and in the country, there have been many research works on the analysis and optimization of the structure of bored pile drilling machines shown
in the documents [19], [35], [60], 62, [66] ] Through these studies, it can be seen that the authors have focused on the following issues and some of the following still exist:
- Optimization of equipment's fuel costs, optimization of structural and working parameters of the equipment has not been mentioned
- Optimizing the steel structure of the box boom and the winch installation position, the optimization of the drilling bucket parameters has not been performed
- Determining the reasonable operating parameters of the bored pile drilling machine whose working set is the bottom expansion bucket but not the vertical cylindrical rotary drilling bucket Optimizing the operating parameters according
to the criterion of maximum bottom expansion yield, not to mention the minimum specific energy criterion The optimization of the structural parameters of the bucket is also not considered
- Optimization of working parameters of bottom expansion bucket with geology in Ho Chi Minh City is different from the type of swing bucket and soil properties of the Northern Delta that the thesis refers to
1.2.3 Overview of research projects on design and manufacture of bored pile drilling machines in Vietnam
Research works on design and manufacture of bored pile drilling machines in Vietnam focus on documents [4], [5], [47]
Objective of [4] is to solve the urgent requirement of localizing the BG36 bored pile drill head assembly The author [4] proposed the required capacity when drilling, this is also the premise for the domestic manufacture of BG36 drill buckets to replace imported equipment
The author [47] focuses on researching, designing and manufacturing drilling work sets in the country Therefore, the research and solving optimization problems to find a reasonable set of drilling bucket parameters have not been mentioned
Trang 8The author [5] has researched, designed, and manufactured a two-motor drive rotary wheel to replace a single-motor drive wheel for bored pile drilling machines This is a research topic that only serves the manufacture of rotary wheels, not a research on the theoretical basis for manufacturing the entire working set of domestic bored pile drilling machines to replace imported equipment
Conclusion of Chapter 1 and research orientation
1 The overview research on the works of domestic and foreign authors on the dynamics of bored pile drilling machines, optimization of bucket design as well
as research on design and manufacture of drilling buckets in the country in Chapter 1 shows that :
In terms of dynamics, the above works mainly introduce methods of calculating machine learning or kinematics of the drill rod, however, the dynamics of the hydraulic transmission system of the machine takes into account the influence of the building foundation has not been mentioned much
In terms of analysis and optimization of the structure of the bored pile drilling machine, the author mainly optimizes the fuel cost, the steel structure of the drill rod, the location of the winch installation , and the optimization of the structural and working parameters of the bucket has not been performed In addition, the determination of the operating parameters of the bored pile drilling machine is mainly done with the bottom expansion bucket, and the cylindrical rotary drilling bucket, including the geology of the Northern Delta, has not been exploited yet
In terms of design and manufacturing of bored pile drilling machines in Vietnam, the main works are research and design technology for machine manufacturing and improvement of drilling technology, while solving the optimal problem to find the reasonable set of parameters of the drill bucket in the mining conditions in Vietnam has not been mentioned
2 On the basis of a general overview of the issues related to the thesis, the content of the next chapters can be determined as follows:
Research on the dynamics of the hydraulic transmission system on the machine takes into account the influence of geological conditions and the foundation of the building From there, the reasonable specifications of the working set are proposed from the dynamic point of view
The research provides computational models to determine the resistance force, the resisting moment acting on the workpiece during the drilling machine working, taking into account the influence of Vietnam's geological conditions From there, research and calculate to determine the required power to drive the motor to rotate the drill
Trang 9Building and solve optimization problems to determine the reasonable specifications of the bucket
Experimental research on bucket drilling machine mounted on Hitachi CX500 crawler crane made in Vietnam
CHAPTER 2:
RESEARCH ON THE DYNAMICS OF THE HYDRAULIC DRIVE SYSTEM OF BUCKET DRILLING MACHINES MADE IN VIETNAM 2.1 Research on the dynamics of the hydraulic transmission system driving the hydraulic motor to rotate the drill plate
Figure 2.2 Dynamic model of the hydraulic transmission system driving the
hydraulic motor to rotate the drill plate
Where: Vb1, Vd1: Specific flow of pump and hydraulic motor 1, m3/rev; Vb2, Vd2: Specific flow of hydraulic pump and motor 2, m3/rev; nb1, nd1 : Number of revolutions of pump shaft and motor 1, rev/s; nb2, nd2 : Number of revolutions
of pump shaft and motor 2, rev/s; pa: Pressure of the working oil in the high pressure branch of the engine, Pa; pt: Pressure of the working oil in the low pressure branch of the engine, Pa; pat: Set pressure of safety valve, Pa; rb1, rd1: Coefficient of flow loss in hydraulic pump 1 and hydraulic motor 1, (m3/s)/Pa;
rb2, rd2: Coefficient of flow loss in hydraulic pump 2 and hydraulic motor 2, (m3/s)/Pa; Ea: Elastic deformation in high-pressure pipeline, m3/Pa; Qb: Total flow of 2 pumps, m3/s; Qb1: Flow of pump No 1, m3/s; Qb2 : Flow of pump No
2, m3/s; Qd: Total required flow through 2 motors, m3/s; Qd1: Flow of motor 1;
m3/s; Qd2: Flow of motor 2; m3/s; Qat : Oil flow through safety valve, m3/s; Mqt1:
Trang 10Moment of inertia of hydraulic motor 1, N.m; Mqt2: Moment of inertia of hydraulic motor 2, N.m; Mc: Torque resisting rotation on the bucket, N.m Mc1: Torque resisting rotation on the shaft of hydraulic motor 1, N.m; Mc2: Torque resisting rotation on the shaft of hydraulic motor 2, N.m
Through setting up the flow equation and force balance, the following system
of differential equations is obtained:
Figure 2.6 Oil pressure in the high
pressure chamber of the hydraulic motor
driving the drill plate
Figure 2.7 Angular velocity of the hydraulic motor driving the drill plate
Figure 2.8 Total power of the hydraulic
motor driving the drill plate
Figure 2.9 Total flow of oil supplied to the hydraulic motor driving the drill
Trang 112.2 Research on the dynamics of the hydraulic transmission system to press the drill plate
Figure 2.11 Dynamic model of the hydraulic transmission system of the drill
press cylinder
Where: Vb: Specific flow of pump No 3, m3/rev; nb: Number of revolutions
of pump shaft No 3, rev/s; rb: Flow loss coefficient at hydraulic pump No 3, (m3/s)/Pa; pa: Pressure of the working oil in the high pressure branch of the cylinder, Pa; pt: Pressure of the working oil in the low pressure branch of the cylinder, Pa; pat: Set pressure of safety valve, Pa; Ea: Elastic deformation in high-pressure pipeline, m3/Pa; Qb: Flow of pump No 3, m3/s; Qxl: Required flow to the cylinder, m3/s; Qat: Oil flow through safety valve, m3/s; Fc: Total drag force related to cylinder rolling during working process, N
Using the law of conservation of energy, write the equation for the continuous flow of the working oil in the pipelines and the force balance equation Considering the case when the drill bucket is stuck, it is necessary to press the cylinder to let the drill bucket escape through the jam, we have a system of differential equations describing the operation of the hydraulic transmission system that drives the hydraulic cylinder to force the drill plate down, as follows:
Ea.dpa
dt = Vb.nb.X(t) −
Vb [nb] (1 − ηb)[pb] pa− 2A1 vxl− (pa− pat) Kat
mqd
dve
dt = 2(pa A1− ptA2) ηc+ mqd g − FC
(2.33) Graphs that are the result of solving the system of equations of motion (2.33) are shown as:
Trang 12Figure 2.14 Hydraulic oil pressure in
drill press cylinder
Figure 2.15 Pressing force of drill press
cylinder
Figure 2.16 Velocity of drill press cylinder
2.3 Surveying the factors affecting the dynamic characteristics of the hydraulic transmission system of the bored pile drilling machine
2.3.1 Surveying the influence of geological strata on the dynamic parameters
of the hydraulic transmission system driving the drill plate
After running the program, the results obtained are as follows:
Figure 2.21 Oil pressure in the engine
driving the drill plate for different
geological strata
Figure 2.22 Number of revolutions of the drill plate for different geological
strata
Figure 2.23 Total flow for hydraulic
motor corresponding to different
Trang 13Figure 2.25 Torque on hydraulic motor shaft for different geological strata
2.3.2 Surveying the parameters affecting the dynamic parameters of the hydraulic cylinder pressing the drill plate
With the Matlab Simulink program built in Figure 2.13, other input parameters are considered unchanged according to Table 2.2 in the explanation, conduct a survey when changing the diameter of the drill press cylinder (D = 100 mm; D = 110 mm; D = 130 mm) and change the resistance acting on the drill press cylinder (Fc = 16000 N; Fc = 22000 N; Fc = 26000 N), the results are shown
as the following figures:
Figure 2.36 Oil pressure in cylinder
presses drill plate when changing