1. EPB shield pressure management
【Formula】The upper and lower limits of the method, the calculation of the variable row twist repair
(1) In the construction of EPB shield, in order to ensure the stability of the excavation face, the pressure of the earth silo should be properly maintained. In general, if the pressure of the soil silo is insufficient, the risk of water inrush or collapse of the excavation face will increase. If the pressure is too high, it will cause the cutterhead torque or thrust to increase, and the propulsion speed will decrease or the ground will bulge.
(2) The basic idea of soil silo pressure management is: as the upper limit, the static earth pressure is used for the purpose of controlling the settlement of the ground surface as much as possible; As a lower limit, a small amount of surface settlement can be allowed, but active earth pressure is used for the purpose of ensuring the stability of the excavation face.
(3) To grasp the steady state of the excavation face, the pressure of the soil bin is generally determined by the earth pressure gauge arranged on the partition.
(4) In the process of propulsion, the pressure of the soil silo is maintained in the following ways; (1) The number of revolutions controlled by the spiral dumper; (2) the propulsion speed control of the shield jack; (3) Combined control of the two, etc. Usually the shield equipment adopts a combined control method.
(5) Implement good management according to each construction condition. In addition, it is necessary to check the deformation of the foundation, the state of soil discharge, the torque of the cutterhead, and the changes in the ground caused by the advancement, and to correct the pressure of the soil bin in a timely manner during the advancement.
2. EPB shield discharge management
【Formula】Pressing and digging with management, and transferring the volumetric weight platform
(1) The pressure management of the pressure chamber and the management of the excavation soil are carried out at the same time to control the collapse of the excavation face or the settlement of the foundation.
(2) The methods of soil discharge management can be roughly divided into volume management method and weight management method. As a volumetric management method, it is generally calculated by calculating the number of muck trucks or by calculating the number of revolutions of the screw discharger. The weight management method is generally to use the weight of the muck truck for acceptance. The method of calculating the number of muck trucks is a rough estimate, which is widely used in the field due to its simple application.
3. The characteristics of the earth pressure balance shield to improve the muck
【Formula】The plastic flow is viscous and low-force
The amount of muck discharged from the EPB shield must be matched to the excavation volume in order to obtain a stable and suitable support pressure value for the TBM to work optimally. When the ideal excavation state cannot be reached by adjusting the rotation speed of the screw conveyor, it can be adjusted by improving the plastic flow state of the muck.
In EPB mode, the muck should have the following characteristics:
1) Good plastic flow condition:
2) Good viscosity.
3) Low internal friction.
4) Low water permeability.
4. Improve the material of the muck
【Formula】Foam bulking pulp
When the muck cannot meet these requirements, it is necessary to improve the muck by injecting improved materials into the cutterhead, soil silo and screw conveyor, and the commonly used improved materials are foam or bentonite slurry.
5. Key points of earth pressure balance shield tunneling
【Formula】Full warehouse pressing soil level, supervising and regulating the setting of references
(1) The excavated muck should be filled with the soil silo, and the pressure of the soil silo formed by the muck should be balanced with the water and soil pressure outside the cutterhead excavation face, and the amount of soil discharged should be balanced with the amount of excavated soil.
(2) The tunneling parameters such as shield cutterhead speed, tunneling speed and soil silo pressure should be set according to the tunnel engineering geology and hydrogeological conditions, buried depth, line plane and slope, surface environment, construction monitoring results, shield attitude and experience in the starting stage.
(3) During the tunneling, the operation of the shield, the changes of the tunneling parameters and the discharge of the muck should be monitored and recorded, and the feedback should be analyzed and fed back in time, and the tunneling parameters and the attitude of the shield should be controlled.
(4) According to the engineering geology and hydrogeological conditions, the improver should be injected into the front of the cutterhead and the soil silo, and the muck should be in a flow plastic state.
Yesterday 速记口诀5/11
1. Shield construction stage division
Excavate and collect
2. The role of soil reinforcement of the cave door
Water and soil pressure anti-deformation
3. The scope and common methods of soil reinforcement at the entrance of the cave
32 strong seepage, deep stirring and spinner, freezing price is high
4. Risk prevention and control of soil reinforcement at the entrance of the cave
The effect is surged, the parameter gap selection is controlled, and the low permeability of the drill core is stable
5. Treatment of soil instability at the entrance of the cave
Small sprays are severe
6. The construction process of shield starting
The shield frame is removed, and the dense core is excavated
7. Determination of the initial excavation length
Friction resistance is followed by growth
8. Excavate the key points of construction
Check and break the door to seal the gap, and the negative nuclear split control and supervision
9. The shield receives the construction process
The end solid chisel seat is sealed and excavated
10. Shield receiving method
Conventional steel jacket water
11. The key points of the shield receiving construction
The earth gate shield posture digs a tight gap
Three days ago, shorthand mantra 5/9
1. The type of shield is classified according to the form of supporting strata
Natural mechanical earthy gas
2. The type of shield is classified according to whether the excavation face is closed
Water and soil hand half machine
3. The type of shield is classified according to the shape of the section
Round horseshoe, multi-class moment
4. The configuration of the cutterhead of the shield machine
Body knife measuring rod tube
5. Cutterhead design matters
The structure uses an open knife
7. The function of the cutterhead
Dig and stir
8. The applicability of the shield to geological conditions
The soil is clay, muddy and watery
9. Selection basis
Survey and set up a broken safety ring, and the field period is auxiliary to the class
10. The basic principles of selection
Fit for the first time
11. Requirements for shield selection and configuration
The shell disc drives the cylinder with snail mud, and changes the human reaming guide
Seven days ago, shorthand mantra 5/5
1. The form of foundation pit support structure
Inner steel concrete, outer anchor soil
2. Support system
The beam force is attached to the column diagonal
3. The retaining stress transmission path of the supporting structure
Wall crown (purlin) brace
4. Steel pipe support
Afterburner encryption and readdition
5. The form requirements of the internal support architecture
Leveling force is applied continuously
6. The principle of internal support system layout
Co-lead excavation and transportation platform
7. Construction of internal support system
Transmit force along the dense pressing and dismantling plate
Two weeks agoShorthand mantra 4/28
1. Cut-and-cover construction of subway stations
Excavate the structure and fill it, and the slope is not sloped
2. Advantages and disadvantages of the open cut construction method of subway stations
How fast and good (quality) is saved (construction period, cost), affecting the environment
3. The construction process of the cut-and-cover method of the subway station
The bottom layer of the water is excavated, and the middle top of the wall is dismantled and dismantled
4. Subway station cover excavation method
Dig and cap the top, and cover the row. Straight and backward
5. Advantages and disadvantages of subway station cover excavation method
Deformation affects the long, horizontal joints of the space excavated
6. Cover digging method:
Cover the bottom of the digging and apply the top of the wall
7. The construction process of cover digging and excavation method
Construct wall slab digging braces
8. Cover digging reverse method:
The perimeter plate is dug and applied to the edge
9. The construction process of cover digging reverse method
Excavated in the top fill of the perimeter column
10. The construction process of cover digging semi-reverse method
The top of the fence is filled and excavated, and the bottom wall is braced
11. Spray anchor excavation method
Deep and dense busy and strict, the control grid anchor needle is nearly shallow
12. Construction steps of shallow buried underground excavation method
Pipe into the short digging of the first water two
13. Applicable conditions for shallow buried underground excavation
The water is steady
14. Soil self-reliance
Foot first branch
15. Selection of commonly used single-span tunnel shallow buried underground excavation method (according to the size of the excavation section)
The platform is separated by a pit on both sides, and the arch column layer is a hole pile
16. Construct the station structure by open cut method
Rectangular frame arch, spanning stacks. Plate wall beam and column bearing type
17. Cover excavation method to construct the station structure
Rectangular frame soft pile
18. Spray anchor excavation (mine) method to construct the station structure
Auxiliary construction of arch layer
五周前速记口诀4/8
1. Design and verification of templates, brackets and arches
The knot is rigid and stable, the pre-arching force of the load, the rod base is set with a symbol, and the rigidity is checked and the anti-tilt is checked
2. Load combination when designing templates, brackets and arches
12 self-weight, 5 side pressure, 3 walks, 4 vibrations, 6 tilting, wind and snow heat preservation 7 water, rigid and strong static movement.
3. The deformation value of the formwork, bracket and arch
Lu Lu 4 Bai Yin 25, 500 hoops 1.5.
4. The construction precamber of the formwork, bracket and arch should be considered
Bullet non-bullet pre-sinking
5. Production and installation of brackets and arches
The pressure base is forbidden to bubble and frozen, the column is in the middle of the hole, the support is not altogether, and the pressure frame is inspected in multiple layers.
6. Provisions for the removal of formwork, brackets and arches
Non-damage, bearing weight, no collapse in the core.
7. Regulations on the unloading of mortar stone and concrete block arch bridges
Pulp 80, small finish, solid arch protection, large empty arch horizontal
8. The principle of cyclic dismantling of formwork, bracket and arch
Split longitudinal and horizontal