Design method of intelligent trolley for full-process integrated construction of inclined shaft with large section and high abrupt slope

Abstract

The invention discloses a large-section high-abrupt-slope inclined shaft full-process integrated construction intelligent trolley design method. The trolley is used for a water diversion inclined shaft of a hydropower station. The method comprises the steps that 1, the load of the trolley is calculated; step 2, carrying out finite element analysis on the trolley; step 3, calculating and rechecking the safety of the trolley; the trolley is divided into six parts including a needle beam module, an inner frame module, a template module, an inclined strut module, a stabilizer bar component and a pin shaft component, and stress nephogram representation and safety calculation are carried out respectively; step 4, calculating and re-checking the safety of the track; and 5, calculating and rechecking the safety of the bent section structure. According to the large-section high-abrupt-slope inclined shaft full-process integrated construction intelligent trolley design method, the bearing capacity of the trolley when the trolley works in the large-section high-abrupt-slope inclined shaft can be accurately calculated, so that the reliability of trolley operation is evaluated, and the operation safety is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel engineering, and in particular relates to a design method for an intelligent trolley for full-process integrated construction of a large-section, high-steep-slope inclined shaft. Background Art

[0002] A lining trolley, or lining trolley, is a mobile work platform specifically designed for tunnel lining construction. It is primarily used for secondary lining construction in tunnels for hydropower projects, single- and double-track railways, and double- and triple-track highways. Lining trolleys offer advantages such as precise tunnel contour shaping, smooth lining surfaces, low cost, reliable structure, easy operation, and rapid lining times. The use of lining trolleys in tunnel lining construction not only speeds up construction but also ensures the quality and safety of the tunnel lining. Operators utilize positioning devices such as the trolley's track clamps and base screw jacks to accurately maneuver the trolley into the construction location and secure it. The lining trolley's formwork system is then assembled into a three-dimensional formwork structure according to the tunnel design drawings. Next, concrete pouring takes place, a critical step in the lining trolley's operation. After the concrete has solidified within the formwork and reached its designed strength, demolding is performed. During trolley operation, the trolley's safety performance must be analyzed to ensure safe operation.

[0003] The Lawa Hydropower Station is located in the upper reaches of the Jinsha River. The water diversion tunnel includes the tunnel entrance gradient section, the upper flat section of the water diversion tunnel, the upper curved section of the inclined shaft, the inclined shaft section, the lower curved section of the inclined shaft, the lower flat section of the water diversion tunnel, and the steel lining section of the lower flat section of the water diversion tunnel. The inclined shaft is about 100m long and has a slope of 55°. The cross-section is fully circular with a net cross-section size of 10m. The lining thickness is 80cm. A single water diversion inclined shaft consists of an upper curved section, an inclined straight section, and a lower curved section. The inclined straight section has an inclination angle of 55°, the upper curved section is 27.898m long, the inclined straight section is 102.244~105.325m long, and the lower curved section is 32.397m long. The secondary lining is constructed in a full circle using a trolley, with each working cycle of 6 meters. Figure 1 shown.

[0004] Due to the unique structure of the Lawa Hydropower Station, existing technology lacks a design method for trolleys operating in the hydropower station's water diversion shaft, particularly one that calculates trolley loads. Ensuring the safety of trolleys operating in the Lawa Hydropower Station's large, steep, and inclined shafts presents a technical challenge. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a design method for an intelligent trolley for integrated construction of large-section, high-steep-slope inclined shafts throughout the entire process. The method can accurately calculate the carrying capacity of the trolley when working in the large-section, high-steep-slope inclined shaft of the Lawa Hydropower Station, thereby evaluating the reliability of the trolley operation to ensure operational safety.

[0006] The trolley is used for the water diversion inclined shaft of a hydropower station, and comprises:

[0007] Step 1: Calculation of trolley load; trolley load calculation includes calculation of trolley deadweight load, calculation of concrete force on trolley, and calculation of trolley load on track; trolley deadweight load calculation includes calculation of trolley dead load and trolley live load. Trolley dead load includes inner frame, needle beam, formwork, steel platform, walkway railing, lateral mechanical jack between single beam frame needle beam, anti-fall baffle, walking wheel, tail diagonal brace, stabilizer bar, middle diagonal brace, plumb cylinder guide column, connecting jack between formwork and single beam frame, high-end walking beam, high seat and cross connection, walkway pull rod in formwork, walking beam; trolley live load includes working equipment, steel bars, operators, etc.; calculation of concrete load force on trolley includes calculation of normal force, tangential force, and lateral force, where the tangential direction is parallel to the longitudinal centerline of the inclined shaft, and the normal direction is perpendicular to the 55° inclined plane; where the normal force of concrete on trolley, the load perpendicular to the 55-degree inclined plane is:

[0008] F 混 =(G 砼 )×cos55°, G 砼 is the actual weight of the concrete;

[0009] The tangential force of concrete on the trolley is the tangential component of the concrete's own weight minus the support provided by the old concrete. The friction force parallel to the slope at all points on the cross section is calculated by integration to obtain the value of the overall friction force.

[0010]

[0011] Where: γ is the specific gravity of concrete; l is the pouring length; t is the pouring thickness; μ is the friction coefficient; R is the radius of the section; θ is the angle between [0, π]; V is the concrete volume;

[0012] The lateral pressure exerted by concrete on the formwork is:

[0013] F=0.28r c t0β1β2V 0.5 ;

[0014] Where: r c is the deadweight of concrete; t0 is the initial setting time of concrete; β1 is the correction coefficient for the effect of admixtures, which is 1.0 when no admixtures are added and 1.2 when admixtures with retarding effect are added; β2 is the correction coefficient for the effect of slump, which is 0.85 when the slump is less than 30mm; 1.0 when the slump is 50-90mm; and 1.15 when the slump is 110-150mm.

[0015] V is the pouring speed of concrete, which is 1.5m / h;

[0016] Step 2: Perform finite element analysis on the trolley;

[0017] Step 2.1: Use ABAQUS, a finite element analysis software, to model each part of the trolley for stress analysis. The overall trolley model is split into a combined model of the template, inner frame, and needle beam. During modeling, the inner frame is modeled using beam elements, the template is modeled using shell elements, and the hydraulic jack connection between the template and inner frame is also modeled using beam elements.

[0018] Step 2.2: Set material and section properties;

[0019] Step 2.3: Apply loads to the model. The loads on the trolley include: its own weight calculated by the program; the tangential and normal forces of the concrete, applied as a uniformly distributed load on the upper semicircular surface of the trolley template; and the lateral loads.

[0020] Step 2.4: Analysis step setting and mesh element division;

[0021] Step 3: Calculation and review of trolley safety;

[0022] Step 4: Track safety calculation and review;

[0023] Step 4.1: Anchor bolt calculation and verification: Use the embedded parts method or through-wall bolt method to calculate the anchor bolt stress under both walking and pouring conditions; verify the strength of the concrete around the anchor bolt.

[0024] Step 4.2: Calculate and verify the slot safety under walking and pouring conditions respectively;

[0025] Step 4.3: Check the concrete stress under the track cushion;

[0026] Step 4.4: Calculate and verify the track base plate, including the shear resistance verification of the track base plate bolts and the weld verification of the track base plate lugs;

[0027] Step 5: Calculation and review of the structural safety of the curved section;

[0028] Step 5.1: Calculation and verification of the upper bend section. The calculation and verification of the upper bend section mainly revolve around the design and safety verification of the scaffolding, including the safety verification of the vertical poles, horizontal poles, main and secondary beams;

[0029] Step 5.2: Verify the safety of the arch frame supported by the formwork in the lower bend section.

[0030] Furthermore, in step 4.1, the through-wall bolt method is used for calculation, including the calculation of the design value of the bearing capacity of each bolt in shear alone:

[0031]

[0032] Where, is the design value of the bolt shear strength; d is the bolt rod diameter;

[0033] Furthermore, in step 4.2: slot calculation and verification, the calculations for walking conditions and pouring conditions include local compression and shear calculations.

[0034] Furthermore, in step 4.4: calculation and verification of the track base plate, the bolts used in the shear resistance verification of the track base plate bolts are M20, each base plate has 6 bolts, and in the weld verification of the track base plate ear plate, each base plate has 4 plates fixed with welds.

[0035] Furthermore, step 2.4: analysis step setting and mesh unit division, in which the analysis step adopts the static general analysis step; the beam unit adopts the B31 unit provided by ABAQUS, and the shell unit adopts the S4R unit provided by ABAQUS for mesh division.

[0036] Furthermore, step 3: trolley safety calculation and review, wherein the trolley is divided into six parts: needle beam module, inner frame module, template module, diagonal support module, stabilizer rod component, and pin shaft component.

[0037] Furthermore, step 5: calculation and verification of the safety of the curved section structure, which mainly includes the design and safety verification of the upper curved section scaffolding and the template modeling and safety verification of the lower curved section.

[0038] The advantages and beneficial effects of the present invention are:

[0039] Through trolley design, the present invention targets the situation of Lawa Hydropower Station, analyzes the overall performance of the trolley and the deformation and load-bearing capacity of the structure under the action of load when the trolley is in operation, demonstrates the reliability of the trolley operation, and forms guiding suggestions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 It is a schematic cross-sectional view of a water diversion tunnel of the present invention;

[0042] Figure 2 It is a schematic diagram of the force transmission path of the trolley of the present invention;

[0043] Figure 3 It is a schematic diagram of the initial state of the trolley of the present invention;

[0044] Figure 4 This is a schematic diagram of the trolley in the walking state of the present invention;

[0045] Figure 5 This is another schematic diagram of the trolley in the walking state of the present invention;

[0046] Figure 6 This is a schematic diagram of the trolley casting state of the present invention;

[0047] Figure 7 It is a schematic cross-sectional view of the trolley of the present invention;

[0048] Figure 8 is a schematic side elevation view of the trolley of the present invention;

[0049] Figure 9 This is a schematic diagram of the direction of the force exerted by concrete on the trolley according to the present invention;

[0050] Figure 10 This is a schematic diagram of the force transmission in the normal direction of concrete according to the present invention;

[0051] Figure 11 It is a schematic cross-sectional view of the portion above the central axis of the diversion tunnel inclined shaft of the present invention;

[0052] Figure 12 It is a schematic side elevation view of the casting section and the front cast section of the trolley of the present invention;

[0053] Figure 13 This is a schematic side elevation diagram of a 6m section during casting of a trolley according to the present invention;

[0054] Figure 14 This is a schematic diagram of concrete tangential force transmission and analysis according to the present invention;

[0055] Figure 15 is a side elevational schematic diagram of the trolley of the present invention;

[0056] Figure 16 It is a cross-sectional schematic diagram of the diversion tunnel inclined shaft of the present invention;

[0057] Figure 17 It is the concrete lateral pressure calculation distribution diagram of the present invention;

[0058] Figure 18 It is a cross-sectional schematic diagram of the trolley of the present invention in another direction;

[0059] Figure 19 It is a schematic diagram of the inner frame model of the trolley of the present invention;

[0060] Figure 20 It is a schematic diagram of the needle beam model of the trolley of the present invention;

[0061] Figure 211 is a schematic diagram of the overall model of the trolley of the present invention in a traveling state;

[0062] Figure 22 This is a schematic diagram of the overall model of the trolley of the present invention in the pouring state;

[0063] Figure 23 It is a schematic diagram of the calculation of the lateral load of each section of the trolley of the present invention;

[0064] Figure 24 Schematic diagram of the load application method of the trolley of the present invention when it is empty;

[0065] Figure 25 It is a schematic diagram of the load application method of the trolley of the present invention in the pouring state;

[0066] Figure 26 This is a schematic diagram of the trolley restraint method of the trolley of the present invention when the trolley is empty;

[0067] Figure 27 Schematic diagram of the trolley restraint mode of the trolley in the pouring condition of the present invention;

[0068] Figure 28 This is a schematic diagram of the force applied to the trolley of the present invention when traveling empty;

[0069] Figure 29 This is a schematic diagram of the force applied to the trolley of the present invention when the trolley is stopped empty;

[0070] Figure 30 This is a schematic diagram of the normal force applied to the trolley of the present invention during the pouring operation;

[0071] Figure 31 This is a schematic diagram of the tangential force applied to the trolley of the present invention during the pouring operation;

[0072] Figure 32 It is a schematic diagram of the calculation of the track anchor of the trolley of the present invention;

[0073] Figure 33 This is a schematic diagram of the local compressive stress analysis of the through-wall bolt of the present invention;

[0074] Figure 34 It is a schematic diagram of the overall dimensions of the anchor rod of the present invention;

[0075] Figure 35 It is a schematic diagram of the dimensions of the anchor rod end portion of the present invention;

[0076] Figure 36 1 is a schematic cross-sectional view of the depth of the anchor rod of the present invention anchored in concrete;

[0077] Figure 37 It is a cross-sectional schematic diagram of the anchor rod of the present invention anchored in the concrete in another direction;

[0078] Figure 38 This is a schematic diagram of the calculation of the track slot of the trolley of the present invention;

[0079] Figure 39 It is a schematic diagram of the weld position of the present invention;

[0080] Figure 40 This is a schematic diagram of the concrete stress on the track cushion layer when the trolley of the present invention is running empty;

[0081] Figure 41 This is a schematic diagram of the force on the track cushion concrete during the pouring process of the present invention;

[0082] Figure 42 It is a schematic diagram of the dimensions of the track base plate of the present invention;

[0083] Figure 43 This is a diagram showing the weld locations at the rail bottom plate lugs of the present invention;

[0084] Figure 44 This is a schematic diagram of the upper curved section formwork support of the present invention;

[0085] Figure 45 This is a schematic plan view of the upright poles of the upper curved section formwork support frame of the present invention;

[0086] Figure 46 This is a schematic cross-sectional view of the portion above the central axis when the reduction coefficient is considered in the present invention;

[0087] Figure 47 This is a schematic cross-sectional view of the portion above the central axis when the safety factor is not considered in the present invention;

[0088] Figure 48 Schematic diagram of the area occupied by a single vertical pole of the present invention;

[0089] Figure 49 It is a schematic diagram of the planar projection area of ​​the scaffold supported on the needle beam of the present invention;

[0090] Figure 50 Schematic diagram of the area occupied by a single horizontal rod of the present invention;

[0091] Figure 51 This is a schematic diagram of the arch support structure of the downward bending section template of the present invention;

[0092] Figure 52 This is a schematic diagram of a finite element model of a downward curved section formwork supporting arch frame of the present invention;

[0093] Figure 53 It is a schematic diagram of the load arrangement of the downward bending section formwork supporting arch frame of the present invention;

[0094] Figure 54Schematic diagram of the arch support constraint arrangement of the downward bending section formwork of the present invention;

[0095] Figure 55 This is a stress cloud diagram of the downward bending section formwork supporting arch frame of the present invention.

[0096] In the figure: 1-weld one, 2-weld two, 3-weld three. DETAILED DESCRIPTION

[0097] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0098] Introduction to the force transmission mode of the trolley, the force transmission mode of the trolley is as follows Figure 2 As shown, the weight of the lining concrete is transferred to the trolley, then from the trolley to the track, and finally from the track to the anchor rod below.

[0099] The trolley's operating conditions and working principles are described below. The trolley's operating conditions are divided into traveling and pouring conditions. First, traveling: The trolley operates in a forward-moving state and a stationary state at the end of its travel. When the trolley is moving forward, two sets of hydraulic cylinders simultaneously act on the trolley. At the end of its travel, only one set of slots bears the trolley's load. Second, pouring: The trolley reaches the target position and begins pouring concrete. The entire weight is shared by the wheels and diagonal braces.

[0100] Working principle of trolley: The working state of trolley is divided into three parts: stop → move → pour. The three steps are carried out in a cycle, as shown in the schematic diagram. Figure 24 As shown:

[0101] 1. Trolley stop (initial) state - the trolley is assembled and the 1st, 2nd and 3rd group of cylinders are in full working condition;

[0102] 2. Trolley travel state 2 - the first group of cylinders is unloaded, the second and third groups of cylinders are loaded, and the trolley is pushed up 500mm;

[0103] 3. Trolley travel state 3 - travels to 600mm, the first group of cylinders is stuck, and the second and third groups of cylinders are retracted;

[0104] 4. Trolley pouring state 4: The 1st, 2nd and 3rd group of cylinders are all in working state. After pouring concrete and removing the formwork, it enters the second cycle working state;

[0105] Trolley load calculation: The load calculation is divided into three parts: calculation of the trolley's own weight load, calculation of the force exerted by the concrete on the trolley and calculation of the load exerted by the trolley on the track; considering that the old poured concrete has a supporting effect on the newly poured concrete, the normal, tangential and lateral forces exerted by the concrete on the trolley are calculated separately.

[0106] Step 1: Calculation of trolley deadweight load:

[0107] The cross-section and side elevation of the trolley are as follows: Figure 7 and Figure 8 As shown, the basic components of the trolley can be divided into trolley template, inner frame, needle beam, jack and oil cylinder;

[0108] The actual weight distribution of the trolley is shown in Table 2-1. The weight of the trolley is strictly controlled during production, and the trolley is weighed according to the actual weight;

[0109] Table 2-1 Trolley constant load

[0110]

[0111] From Table 2-1, we can see that the constant load of the trolley is 148t.

[0112] The live load capacity of the trolley is shown in Table 2-2:

[0113] Table 2-2 Trolley live load

[0114]

[0115] Considering the live load partial coefficient (value 1.4), live load: (1+2+0.5)×1.4≈5t, the total weight of the trolley's dead load and live load is 148+5=153t.

[0116] Concrete load on the trolley:

[0117] Considering that the old poured concrete has a supporting effect on the new poured concrete, the gravity of the concrete is decomposed into normal and tangential directions. Figure 9 As shown, the tangential direction is parallel to the longitudinal centerline of the inclined well, and the normal direction is perpendicular to the 55-degree inclined plane.

[0118] (1) Normal force:

[0119] Considering the force calculation under the unloading effect of the poured concrete, the calculation principle diagram is shown in Figure 2-4. The normal effect of the concrete on the trolley can be expressed as the normal separation of the concrete's own weight minus the load provided by the old concrete to support it.

[0120] When the trolley is pouring, the maximum pressure of the newly poured concrete on the steel formwork is calculated by only considering the part above the center axis of the water diversion tunnel, that is, half of the concrete weight. Figure 11 As shown:

[0121] The tunnel's secondary concrete lining thickness is 800mm, with overcut calculated as 100mm, for a total concrete thickness of 900mm. Considering a partial factor of 1.4 and the impact load effect during concrete pouring, and in accordance with Appendix A.0.6 of the "Concrete Structure Engineering Construction Code" (GB50666-2011), a standard value of 2% of the weight of concrete and steel on the formwork is used. The concrete thickness is 900 × 1.4 × (1 + 2%) = 1285 (mm).

[0122] After multiplying by the partial coefficient, the thickness of the concrete is 1.285m. In order to simplify the calculation, the concrete thickness is taken as 1.3m for calculation.

[0123] The volume of the part above the central axis is:

[0124] V=πrhl

[0125] Where: r is the radius of the circle, which is equal to the sum of half the concrete thickness and the tunnel radius, and is r = 5.65m; h is the concrete thickness, and is taken as h = 1.3m; l is the length of each section of poured concrete, and is taken as l = 6m.

[0126] So V=3.14×5.65×1.3×6=139(m 3 ), the volume of concrete poured in each section is 139 (m 3 ).

[0127] Consider the unloading effect of concrete after pouring, such as Figure 12 As shown in the figure, the concrete poured in the previous section will provide an oblique upward support force to the road section being poured; Figure 13 As shown, the weight of EDACBF is not calculated. When it is poured above the center of gravity, the concrete poured below will provide it with support. Therefore, the weight of FGB below the center of gravity is discarded, and only the weight of the concrete in the shaded area of ​​HICBG is calculated.

[0128] The normal force of concrete on the trolley is calculated as follows:

[0129] AC length:

[0130] L AC =L AB ×tanα

[0131] Where: L AB is the length of side AB, α is the slope of the tunnel, and α=55°.

[0132] L AC =3×tan 55°=4.28m

[0133] The actual arc length of AB is:

[0134]

[0135] Where: d is the diameter of the circle, take d = 6m.

[0136]

[0137] Considering the unloading effect after concrete pouring, the concrete volume that needs to be deducted is:

[0138]

[0139] Where: is the actual arc length of AB, take L AC is the length of AC, take L AC =4.28m; h is the thickness of concrete.

[0140]

[0141] Actual weight of concrete:

[0142] G 砼 =(139-23.2)×2.5=290(t)

[0143] The normal force of concrete on the trolley, the load perpendicular to the 55-degree slope is:

[0144] F 混 =(G 砼 )×cos55°=(290)×0.574=166.5(t)

[0145] When pouring concrete, the normal pressure of concrete on the trolley is 166.5t;

[0146] (2) Tangential force:

[0147] The calculation principle of the tangential force of concrete on the trolley is as follows: Figure 14 As shown in the figure, the old concrete provides a certain support force to the newly poured concrete, so the tangential effect of the concrete on the trolley can be expressed as the tangential component of the concrete's own weight minus the support force provided by the old concrete;

[0148] During oblique pouring, the concrete is supported in the tangential direction by the concrete already poured at the bottom. The concrete is subjected to the tangential force from the support force of the poured concrete and the friction force of the trolley on the concrete. The friction coefficient between the concrete and the steel formwork is between 0.2 and 0.6. The maximum value is taken as 0.6 in this calculation.

[0149] Using the integral method, such as Figure 15As shown, the newly poured concrete only has friction with the upper part on the steel formwork. The friction of the concrete is related to the pressure of the concrete perpendicular to the steel formwork, as shown in Figure 16 As shown in the cross-sectional diagram, the gravity of each point is decomposed, and the section Ⅰ-Ⅰ is analyzed to obtain the pressure perpendicular to the steel formwork at each point. The friction force parallel to the slope surface of all points in the section is calculated using the idea of ​​integration, and then the value of the overall friction force is obtained:

[0150]

[0151] Where:

[0152] γ is the specific gravity of concrete, which is 2.5t / m 3 ; l is the pouring length, which is 6m; t is the pouring thickness, which is 1.3m; μ is the friction coefficient, which is 0.6; R is the radius of the semicircular section; θ is the angle between [0, π];

[0153] (3) Lateral effect:

[0154] When pouring concrete, the concrete will exert lateral pressure on the formwork.

[0155] F=0.28r c t0β1β2V 0.5

[0156] F=r c h

[0157] Where r c is the deadweight of concrete, take 2.5t / m 3 ; t0 is the initial setting time of concrete, which is taken as 5h; β1 is the correction coefficient for the effect of admixtures, which is 1.0 when no admixtures are added, and 1.2 when admixtures with retarding effect are added. In this calculation, β1=1.2; β2 is the correction coefficient for the effect of slump, which is 0.85 when the slump is less than 30mm; 1.0 when the slump is 50-90mm; and 1.15 when the slump is 110-150mm. In this calculation, β2=1.15; V is the pouring speed of concrete, which is taken as 1.5m / h; h is the total pouring height of concrete;

[0158] The concrete lateral pressure is:

[0159] F=0.28r c t0β1β2V 0.5 =0.28×2.5×5×1.2×1.15×1.5 0.5 =5.92t / m 2

[0160] The calculation distribution diagram of concrete side pressure is as follows Figure 1 As shown, the effective pressure head height h (m) is calculated as follows:

[0161]

[0162] Where: h is the effective pressure head height; F is the maximum side pressure;

[0163] The effective pressure head height is:

[0164]

[0165] Take the effective pressure head h = 2.4m.

[0166] Loads from trolley and lining concrete on track:

[0167] Walking conditions:

[0168] Normal acting load:

[0169] G 法 =G 台 ×cosα

[0170] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°.

[0171] G 法 =153×cos 55°=88t

[0172] Tangentially acting loads:

[0173] G 切 =G 台 ×sinα

[0174] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°.

[0175] G 切 =153×sin 55°=125t

[0176] Casting conditions:

[0177] Normal acting load:

[0178] G 法 =G 台 ×cosα+F 混

[0179] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 混 is the normal force of concrete on the trolley, which is 166.5t.

[0180] G 法=153×cos55°+166.5=254.3t

[0181] Tangentially acting loads:

[0182] G 切 =G 台 ×sinα+F 摩

[0183] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 摩 is the tangential force of concrete on the trolley, which is 67.1t.

[0184] G 切 =153×sin55°+67.1t=192t

[0185] Step 2: Finite element calculation of the trolley.

[0186] The finite element model was established, and the force results of the trolley in various states were obtained through finite element software analysis.

[0187] The cross section and profile of the trolley are as follows Figure 18 and Figure 8 As shown in the figure, its basic components include inner frame, needle beam, template, jack, oil cylinder, etc. However, if all components are taken into account in the finite element modeling, it will make the calculation results difficult to converge. Therefore, the modeling only considers the most important combination model of template + inner frame + needle beam.

[0188] Step 2.1: Use ABAQUS, a finite element analysis software, to model each part of the trolley and perform stress analysis. The overall trolley model is split into a combined model of the template, inner frame, and needle beam.

[0189] When modeling the template + inner frame + needle beam in Abaqus software, the inner frame is modeled using beam elements, the template is modeled using shell elements, and the hydraulic jack connection between the template and the inner frame is also modeled using beam elements. The model is as follows Figure 19-20 As shown:

[0190] (1) The overall model of the trolley in the walking state is as follows Figure 21 As shown, there is no diagonal support in the walking state. The overall model of the trolley in the casting state is as follows: Figure 22 As shown, at this time, the diagonal brace and the stabilizer bar participate in the load;

[0191] Step 2.2: Set the material and section properties: The material used is Q235 steel with a density of 7850kg / m 3, elastic modulus is 210GPa, Poisson's ratio is 0.3; the cross-sectional properties are given according to the construction drawings. The single beam frame adopts No. 12 channel steel, H-shaped steel with sections of H250×250×14×9, H388×402×15×15, H400×300×10×16, and H500×300×12×16mm, and the hydraulic jack adopts a circular section; the needle beam adopts No. C10 channel steel, I-18, I-20B and I-25B I-steels, H-shaped steel with sections of H300×200×12×8, H400×200×8×13, and H400×300×10×16mm; the diagonal brace and stabilizer bar adopt φ121×10mm round tube.

[0192] Step 2.3: Apply loads to the model. The loads applied by the trolley are mainly:

[0193] (1) Self-weight, calculated by the program.

[0194] (2) The tangential force and normal force of the concrete are applied to the upper semicircular surface of the trolley formwork as a uniformly distributed load.

[0195] (3) Lateral load.

[0196] The lateral force is distributed in a triangle at the effective pressure head and uniformly distributed below the effective pressure head. When performing finite element calculations, in order to facilitate loading within the height range of the effective pressure head h, the effective pressure head h is divided into four parts and loaded approximately uniformly. The magnitude of the force remains unchanged, and the calculated resultant force is divided as follows: Figure 23 .

[0197] On a 6m long formwork, the magnitude of the force in each part is as follows, where: a i is the bottom of each part; h i is the height of each part. Due to the equal division, the height of each part is 0.6m, i is 1, 2, 3, 4; l is the length of each casting section, which is 6m.

[0198] Part 1:

[0199]

[0200] Part 2:

[0201]

[0202] Part 3:

[0203]

[0204] Part 4:

[0205]

[0206] The pressure below the effective head is evenly distributed and loaded according to the above calculation results.

[0207] Supplementary loads:

[0208] Since beam elements are used for modeling, there will be some errors between the weight of the model and the actual weight. Therefore, some additional loads will be applied, including 21.1t on the needle beam, 7.1t on the single beam frame, 2.8t on the plumb cylinder guide column, 1.2t on the high-end walking beam heightening seat and cross-connection, 8.4t on the walking beam, 1.5t on the platform tie rod in the template, 4t on the walking wheel, 3.7t on the diagonal brace, 4.1t on the high and low anti-floating brace rods, 5t on the reinforced platform walkway railing, and 5t on the live load.

[0209] In the case of empty vehicle deadweight, considering (1) deadweight of the vehicle and (4) supplementary load, the loading method is as follows Figure 24 As shown:

[0210] In the case of pouring, in addition to considering (1) the deadweight of the trolley and (4) the supplementary load, the normal force and tangential force of the concrete on the formwork, as well as the lateral pressure of the concrete on the formwork before solidification, are added. The load size is shown in the above-mentioned trolley load calculation. The loading method is as follows: Figure 25 As shown;

[0211] Step 2.4: Analysis step settings and mesh element division:

[0212] The analysis step adopts the static general analysis step; the beam element adopts the B31 element provided by abaqus, and the shell element adopts the S4R element provided by abaqus for meshing.

[0213] Model boundary conditions:

[0214] The calculations do not consider wheel tension to avoid a mixed tension-shear state in the anchor bolts. Therefore, the nodes at wheels A, B, C, and D are subject only to compression, not tension. Furthermore, in both the deadweight and pouring scenarios, all constraints are set to hinged to simulate the boundary conditions found in actual working conditions.

[0215] (1) Under deadweight conditions, if Figure 26 As shown, normal constraints are applied to the wheels of group A at the upper end of the needle beam, constraints in two directions are applied to the wheels of group B and C at the lower end of the needle beam, and constraints in three directions are applied to the wheels of group D.

[0216] (2) In the case of pouring, if Figure 27 As shown, normal constraints are applied to the wheels of group A, two-direction constraints are applied to the wheels of group B and C at the lower end of the needle beam, three-direction constraints are applied to the wheels of group D, and three-direction hinge constraints are applied to the upper and lower stabilizer bars, diagonal braces, and large diagonal braces.

[0217] Finite element calculation results:

[0218] The trolley working conditions are divided into three types: when the trolley is traveling empty, when the trolley is stopped empty, and when pouring. Based on abaqus, the above whole model is modeled and the overall force diagram under the three working conditions is obtained. The force transmission conditions are as follows: Figure 28 、 29 , as shown in Figure 30.

[0219] Walking condition, the forces on the two sets of wheels during walking condition are:

[0220] When the trolley is moving empty, two sets of oil cylinders push the wheels to move the trolley. The tangential self-weight is borne by the two sets of oil cylinders, and the normal self-weight is borne by the four sets of wheels. The support reaction diagram is shown in Figure 28. The corresponding force magnitudes and total values ​​of each support are shown in Table 3-1:

[0221] Table 3-1 Stress conditions of trolley components when the trolley is traveling empty

[0222]

[0223] Calculation results when the vehicle is stationary or one group of cylinders fails:

[0224] The empty vehicle stops moving and the two sets of cylinders are retracted. At this time, the tangential self-weight is borne by the slot where one set of wheels is located, and the normal self-weight is borne by all four sets of wheels. The support reaction diagram is shown in Figure 29. The corresponding force magnitudes of each support and the total value are shown in Table 3-2:

[0225] Table 3-2 Stress conditions of trolley components when the empty trolley stops

[0226]

[0227] Casting conditions:

[0228] During the pouring operation, the tangential force and normal force become the sum of the deadweight and concrete, and are borne by the wheels and the diagonal brace. During the pouring operation, the largest diagonal brace is subjected to a normal force of 24.3t and a tangential force of 33t. The support reaction diagrams are shown in Figures 30 and 31. Figure 31 As shown, the corresponding force magnitude and total value of each support are shown in Table 3-3;

[0229] The normal force acting on the trolley during the pouring operation is as follows: Figure 30 As shown;

[0230] The tangential force on the trolley during the pouring operation is as follows: Figure 31 As shown;

[0231] Table 3-3 Stress conditions of trolley components during pouring operation

[0232]

[0233] From the above modeling, it can be seen that the finite element modeling calculation can converge, and it can be seen that the structure is in a stable state, indicating that the trolley will not overturn.

[0234] Step 3: Trolley safety calculation and review:

[0235] The trolley is divided into six parts: needle beam module, inner frame module, formwork module, diagonal brace module, stabilizer rod component, and pin shaft component. Stress cloud diagrams are presented and safety calculations are performed for each part. Because the components will experience greater stress and more dangerous situations when pouring concrete, the stress size and safety calculation of the needle beam under the condition of pouring concrete are given.

[0236] Step 4: Track safety calculation and review:

[0237] Anchor calculation and review:

[0238] Overview of the anchor rods. Since the diversion tunnel is located at a 55° slope, the anchor rods will be subjected to both pressure and shear forces under the action of different force components.

[0239] Tangential force:

[0240] V=F 摩 +G 台 × sinα,

[0241] V=67.1+153×sin55°=192(t);

[0242] Normal force:

[0243] F=G 台 ×cosα+F 混 ,

[0244] F=153×cos 55°+166.5=254.3(t);

[0245] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 摩 is the tangential force of concrete on the trolley, which is 67.1t; F 混 The normal force of the concrete on the trolley is 166.5t.

[0246] (1) Concrete strength calculation:

[0247] The anchor steel bars are Φ30 fine-rolled threaded steel bars as track anchor steel bars. The length of a single track section is 1.5 meters. Three steel bars are used for anchoring with a spacing of 500mm. The design value of the tensile strength of the anchor bar is f y =650N / mm 2However, the bearing capacity of concrete will be affected to a certain extent according to the construction time, such as Figure 32 As shown,

[0248] The concrete strength is calculated as follows:

[0249] f ck =0.88k1k2f cu,k ,

[0250] f c =f ck / φ,

[0251] Where:

[0252] φ is the reduction factor, which is 1.4;

[0253] k1 is the conversion coefficient, which is 0.76;

[0254] k2 is the brittleness coefficient, which is taken as 1.0;

[0255] Under walking conditions and pouring conditions, the concrete is calculated based on the strength of 3 days. After 3 days of concrete pouring, the standard value of the compressive strength of C30 concrete cube is f cu,k =7.5N / mm 2 , at this time the design value of concrete compressive strength is:

[0256] f c =f ck / φ=3.58N / mm 2 ,

[0257] The anchor rods of the trolley were calculated using the embedded parts method and the through-wall bolt method. The calculation results are as follows:

[0258] Step 4.1: Calculate using the embedded parts method, including:

[0259] The anchor rod is approximately regarded as an embedded part. According to the relevant theory of embedded parts, the bearing capacity of the anchor bar in pure shear is checked. d is the diameter of the anchor bar, which is 30mm. The expression of the anchor bar shear bearing capacity is:

[0260] V=α r α v f y A s ,

[0261] in:

[0262] α r is the influence coefficient of the number of anchor reinforcement layers; when the anchor reinforcements are arranged at equal intervals, the coefficient is 1.0 for two layers, 0.9 for three layers, and 0.85 for four layers. In this calculation, the coefficient is 0.9 for three layers.

[0263] α vis the shear bearing capacity coefficient of anchor bar, according to the formula When α v >0.7, take 0.7;

[0264] f y f is the yield strength of steel, y =650MPa;

[0265] A s is the shear area, take A s =πd 2 / 4=3.14×30 2 / 4=707mm 2 ;

[0266] Walking conditions:

[0267] Assume that there are 48 anchor rods from the front wheel A to the trolley wheel D, the concrete strength is calculated based on 3 days, and the design strength is 3.58 MPa; then:

[0268]

[0269] V=0.119×650×707×0.9=54.7(kN),

[0270] Actual shear force on a single anchor rod:

[0271]

[0272] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; g is the acceleration due to gravity, which is 10m / s 2 ; n is the number of anchor rods, which is 48 in total.

[0273] V 实 =153×sin55°×10÷48=26KN

[0274] The safety factor is:

[0275]

[0276] 54.7÷26=2.1

[0277] Casting conditions:

[0278] There are 78 anchor rods from the front wheel A to the diagonal support at the rear end of the trolley. The concrete is calculated based on the strength after 3 days, and the design strength is 3.58MPa.

[0279]

[0280] V=0.119×650×707×0.9=54.7(kN)

[0281] Actual shear force on a single anchor rod:

[0282]

[0283] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 摩 is the tangential force of the concrete on the trolley, which is 67.1t; g is the acceleration due to gravity, which is 10m / s 2 ; n is the number of anchor rods, which is 78 in total.

[0284] V 实 =(153×sin55°+67.1)×10÷78=24.6kN

[0285] The safety factor is:

[0286]

[0287] 54.7÷24.6=2.22

[0288] Step 4.1: Calculate using the through-wall bolt method:

[0289] Consider the anchor rod as a through-wall bolt and calculate the design bearing capacity of each bolt under pure shear (N):

[0290]

[0291] is the design value of the bolt shear strength; 45 steel is approximated as Q345, f y The yield strength of 45 steel is 290N / mm 2 ;f v The shear strength of 45 steel is 170N / mm 2 ;

[0292] d—bolt rod diameter (mm), 30mm is used in this project;

[0293] The design value of the bearing capacity of each bolt in pure shear (N) is:

[0294]

[0295] (1) Anchor force analysis in walking condition:

[0296] When the trolley is running, a single trolley weighs 153t, and the anchor rod is only subjected to the tangential component of the trolley's own weight.

[0297] The actual shear force on a single anchor rod is: V 实 =153×10×sin55°÷48=26kN;

[0298] Safety factor:

[0299]

[0300] (2) Anchor force analysis during pouring:

[0301] The concrete is poured by a trolley. The weight of a single trolley is 153t. The anchor rod is only subjected to the tangential force of the trolley and the tangential force of the concrete. The actual shear force on a single anchor rod is

[0302] V 实 =(153×sin55°+67.1t)×10÷78=24.6kN

[0303] Safety factor:

[0304]

[0305] Verification of concrete strength around anchor rods:

[0306] The analysis diagram is as follows Figure 33 As shown,

[0307] The local compressive strength of concrete at the through-wall bolt hole is calculated according to the following formula:

[0308] R i (i=1,2)≤R

[0309] Where: R is the design value of the local compressive bearing capacity of concrete at the bolt hole (kN / m 2 )

[0310] R=1.35βf c A m

[0311] Where: β is the coefficient of improvement of local compressive strength of concrete, which is taken as 1.73. When the concrete is not completely solidified under the 3-day working condition, the coefficient is taken as 1;

[0312] f c is the design value of the axial compressive strength of the concrete specimen at the climbing age (kN / m 2 ); Here, the design value of the axial compressive strength of the concrete specimen at 3 days of age is taken to achieve: f c =3.58N / mm 2 ;

[0313] A m is the local bearing area of ​​the bolt (m 2 ), Am =db1 or A m =db2, where d is the screw diameter, or the outer diameter of the casing if one is provided, and b1 and b2 are the calculated heights (mm) of the compression zones at the lower and upper parts of the wall, respectively. Figure 34 、 Figure 35 As shown;

[0314] The area of ​​the compressed zone is:

[0315]

[0316] In the formula: a is the upper base of the trapezoid, which is 42mm; b is the lower base of the trapezoid, which is 74mm; h is the height of the trapezoid, which is 150mm; c is the length of the rectangle, which is 100mm; d is the width of the rectangle, which is 30mm.

[0317]

[0318] R1 and R2 are the compressive stresses (kN) generated by the bolt on the concrete below and above the perforation, respectively, which can be calculated as follows:

[0319]

[0320] Where: N V is the design value of the shear force borne by the bolt (kN); in the empty truck condition, the maximum shear force borne by a single anchor rod is 26kN; in the pouring condition, the shear force borne by a single anchor rod is:

[0321]

[0322] Where: V is the tangential force during pouring, which is 192t; g is the acceleration due to gravity, which is 10m / s 2 ; n is the number of anchor rods, which is 78.

[0323]

[0324] c is the distance between the shear force application point and the wall surface (mm), and the thickness of the pad is taken as 16mm;

[0325] b is the wall thickness (mm), and the anchor depth is 800 mm;

[0326] b1 and b2 are the calculated heights of the compression zone at the lower and upper parts of the wall respectively (mm); assuming b1 is (1 / 3 to 1 / 4)b, b2 is (1 / 3 to 1 / 4)b1, then the depth profile of the anchor rod in the concrete and the dimensions of the anchor rod itself are as follows: Figures 36-37 As shown;

[0327] like Figures 36-37As shown, b = 800mm. According to the value standard of the document "Discussion on the Verification of Local Compressive Strength of Concrete at Through-Wall Bolt Holes in JGJ183-2009 Specification", b1 is 250mm and b2 is 67mm.

[0328] (1) Walking conditions:

[0329] Substituting the data under the walking condition into equation (1-1), the solution is:

[0330] Then calculate R:

[0331] R=1.35βf c A m =1.35×1×3.58×10 3 × 0.0117 = 56.5 kN,

[0332] Comparing the R calculated above with R1 and R2, we can see that:

[0333] R i (i=1,2) <R,

[0334] To meet the requirements, the safety factor is:

[0335] Casting conditions:

[0336] Substituting the data under the pouring condition into equation (1-1), the solution is:

[0337] Calculate R:

[0338] R=1.35βf c A m =1.35×1×3.58×10 3 × 0.0117 = 56.5 kN,

[0339] Comparing the R calculated above with R1 and R2, we can see that:

[0340] R i (i=1,2) <R,

[0341] To meet the requirements, the safety factor is:

[0342] Step 4.2: Card slot calculation and review:

[0343] Card slot overview: Card slot is made of Q345 steel, the shape, size and location of the card slot are as follows Figure 38 As shown;

[0344] Walking conditions:

[0345] The trolley travel is divided into the following situations: when the travel stops, only one set of slots fixes the trolley (the most unfavorable situation), when two sets of cylinders are stressed during travel, and when one set of cylinders fails during travel;

[0346] Walking status:

[0347] When the movement is finished, the two groups of cylinders are retracted after their action is completed. At this time, only the slots at the group A wheels are under stress. The axial stress and shear member verification can be calculated according to the following formula:

[0348] F / A≤[σ],

[0349] [σ]=295Mpa,

[0350] (1) Local compressive strength verification:

[0351] Assume a set of wheels consists of two single wheels, each with a clip on both sides. The force on each clip is:

[0352]

[0353] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; n is the number of clips, and n=4 in this case; A is the cross-sectional area of ​​the clip, and the cross-section of the clip is a square with a side length of 40mm. However, considering that the wheel cannot fit completely on the square cross-section, the length of one side is taken as 35mm when calculating the cross-sectional area.

[0354]

[0355] Safety factor:

[0356] (2) Shear resistance calculation:

[0357] When calculating the shear resistance of the clip, the cross section of the clip becomes a rectangle with a length of 250 mm and a width of 40 mm. The area at this time is A = 250 × 40 = 10000 mm 2 .

[0358]

[0359] Safety factor:

[0360] When one set of cylinders fails during travel, only one set of cylinders bears the tangential force of the trolley's own weight. The situation at this time is the same as the process and results of the above calculation.

[0361] Casting conditions: During casting, the slots under the three sets of wheels of the trolley are subjected to force at the same time:

[0362] (1) Local compressive strength verification:

[0363] The forces acting on a set of wheels are:

[0364]

[0365] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 摩 is the tangential force of the concrete on the trolley, which is 67.1t; n is the number of wheel sets, and n=3 in this case; A is the cross-sectional area of ​​the clip. The cross-section of the clip is a square with a side length of 40mm, but considering that the wheel cannot fit completely on the square cross-section, the length of one side is taken as 35mm when calculating the cross-sectional area.

[0366]

[0367] The other set of wheels is held in place by four clips:

[0368]

[0369] Safety factor:

[0370] Take [σ] = 295MPa to meet the requirements.

[0371] (2) Shear resistance calculation:

[0372] When calculating the shear resistance of the clip, the cross section of the clip becomes a rectangle with a length of 250 mm and a width of 40 mm. The area at this time is A = 250 × 40 = 10000 mm 2 .

[0373]

[0374] Safety factor:

[0375] Calculation of slot weld strength:

[0376] The weld adopts equilateral right-angle fillet weld, and the welding material is E43 welding rod; Figure 39 As shown, the length of a single track section is 1.5m. The side square rack is connected to the middle box track through weld 1 and weld 2. The middle box track is connected to the bottom steel plate through weld 3. The strength of weld 1, weld 2, and weld 3 needs to be verified.

[0377] When subjected to a force parallel to the length of the weld, it can be calculated as follows:

[0378]

[0379] τ fAccording to the effective section strength of the weld;

[0380] h e is the calculated thickness of the right-angle fillet weld, h e =0.7h f =7mm;

[0381] h f is the leg size of the fillet weld, take h f =10mm;

[0382] l w The calculated length of the fillet weld is calculated using the formula l w =1-2h f Calculation: The length of the upper weld 1 is l w =250-2×10=230mm, the length of the lower weld 2 is l w =1500-2×10=1480mm, the length of the lower weld 3 is 1480mm, l is the length of a single slot, and the size is 250mm;

[0383] is the strength design value of the fillet weld. When the welding rod is E43,

[0384] (1) Empty car situation:

[0385] The force on a single-sided weld is:

[0386]

[0387] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; n is the number of sides where the welds are located. The trolley has two tracks, and one track has welds on both sides, so n=4.

[0388]

[0389] The strength of welds 1 and 2 are both:

[0390]

[0391] The strength of weld 3 is:

[0392]

[0393] The safety factor is:

[0394] (2) Casting conditions:

[0395] The force on a single-sided weld is:

[0396]

[0397] Where: G 台 is the weight of the trolley, which is 153t; α is the slope of the tunnel, which is 55°; F 摩 is the tangential force of concrete on the trolley, which is 67.1t; n is the number of sides where the welds are located. The trolley has two tracks, and one track has welds on both sides. When pouring concrete, the load is shared by three sets of slots, so n=4×3=12.

[0398]

[0399] The strength of welds 1 and 2 are both:

[0400]

[0401] The strength of weld 3 is:

[0402]

[0403] The safety factor is:

[0404] Step 4.3: Check the concrete stress under the track cushion:

[0405] Traveling condition: Under the traveling condition, the maximum pressure on the wheel surface of the trolley A is 21.9t. The force diagram of the track cushion concrete under the empty vehicle traveling condition is shown in FIG40.

[0406] The maximum pressure on the wheel surface of the trolley A is F A =21.9t, the support pad thickness is t1 = 10mm, the vertical block width is t2 = 20mm, the horizontal length is l1 = 500mm, and the diagonal length is l2 = 533mm. In the following formula, n is the number of protrusions under a single track plate, and n = 3.

[0407] The force acting on a single support is:

[0408]

[0409] The slope angle at the support is 20.5 degrees, and the normal force at a single support is:

[0410] F 法 =Fcos 20.5°=7.3×cos20.5°=6.84t

[0411] Since the force is transmitted in the direction of 45°, the force width is:

[0412] D=2×(t2+2t1)=2×(20+10×2)=80mm

[0413] The force-bearing area is:

[0414] A=l2×d=533×80mm=42640mm 2

[0415] The local compressive stress in concrete is:

[0416]

[0417] The compressive strength of concrete after 3 days is [σ] = 3.58 MPa, and the safety factor is:

[0418]

[0419] Casting conditions: Under casting conditions, the maximum pressure of the trolley is 41t. When the empty trolley is traveling, the track cushion concrete is subjected to stress under the overturning action. Figure 41 As shown,

[0420] The maximum pressure on the wheel surface of the trolley A is F A =41t, the support pad thickness is t1 = 10mm, the vertical block width is t2 = 20mm, the horizontal length is l1 = 500mm, and the diagonal length is l2 = 533mm. In the following formula, n is the number of protrusions under a single track plate, and n = 3.

[0421]

[0422] The slope angle at the support is 20.5 degrees, and the normal force at a single support is:

[0423] F 法 =Fcos 20.5°=13.7×cos20.5°=12.8t

[0424] Since the force is transmitted in the direction of 45°, the force width is:

[0425] d=2×(t2+2t1)=2×(20+10×2)=80mm

[0426] The force-bearing area is:

[0427] A=l2×d=533×80mm=42640mm 2

[0428] The local compressive stress in concrete is:

[0429]

[0430] The compressive strength of concrete under pouring conditions is [σ] = 3.58 MPa, and the safety factor is:

[0431]

[0432] Step 4.4: Calculation and verification of track base plate: The specific dimensions of the track base plate are as follows: Figure 42 As shown:

[0433] Shear resistance verification of track base plate bolts:

[0434] The bolts are M20, and each base plate has 6 bolts. According to the finite element calculation results in step 2, the maximum tangential force on the track is 630kN, which is evenly shared by the two tracks. The force on the pad under one track is 315kN.

[0435] Therefore, it is necessary to verify the end bolt connection strength, using 8.8 grade, M20 bolts, f t =400N / mm, f v =250N / mm, the design value of the shear bearing capacity of each bolt is:

[0436]

[0437] A e is the effective bolt area, d e is the effective diameter of the bolt, take d e =20mm, so A e =244.8mm 2 ;

[0438] The total shear force that the 6 bolts can withstand is: 97.92×6=367.2kN

[0439] Safety factor: 367.2÷315=1.20;

[0440] Verification of weld seams at the rail bottom plate ear plate: The weld seam position is as follows: Figure 43 As shown, each base plate has 4 plates fixed with welds;

[0441] The calculation method for the weld seam at the rail bottom plate ear plate is the same as the calculation method for the needle beam weld seam mentioned above, and is calculated as follows:

[0442]

[0443] τ f is the shear stress along the length of the weld, calculated based on the effective cross-section of the weld;

[0444] h e is the calculated thickness of the right-angle fillet weld, h e =0.7h f =7mm;

[0445] l w The calculated length of the fillet weld is calculated using the formula l w =1-2h f calculate;

[0446] h f —The leg size of the fillet weld is h f =10mm;

[0447] A single connector is welded on all four sides, with side lengths of l1 = 65 mm and l2 = 80 mm. To calculate the weld, multiply by 2, so the total weld length is: l w =2×(l1-2h f )+2×(l2-2h f )=(65-20)×2+(80-20)×2=210mm

[0448] Total length of weld seams of 4 top panels: 210×4=810mm

[0449] According to the finite element calculation results in step 2, the maximum tangential force on the track is 630kN, which is evenly shared by the two tracks. The force on the pad under one track is 315kN.

[0450]

[0451] Safety factor:

[0452] Step 5: Calculation and review of curved section structural safety

[0453] Including the design and safety verification of the upper curved section scaffolding and the template modeling and safety verification of the lower curved section;

[0454] Step 5.1: Calculation and verification of the upper bend section. The calculation and verification of the upper bend section revolve around the design and safety verification of the scaffolding.

[0455] During the construction of the upper bend section, since the trolley cannot continue to work, it is necessary to build a scaffolding for construction. One end of the scaffolding is built on the tunnel wall, and the other end is built on the needle beam at the lower end of the trolley. Figure 44 As shown;

[0456] Load calculation:

[0457] When calculating the load, the weight of the scaffolding supported on the needle beam, the weight of the formwork, and the weight of the concrete in one construction section were taken into account. The actual weight of the formwork is N1 = 15.4t, and the actual weight of the scaffolding is N2 = 53.0t. Considering the partial factor of 1.2, the calculated weight of the formwork is N′1 = 15.4 x 1.2 = 18.5t, and the calculated weight of the scaffolding is N′2 = 53.0 x 1.2 = 63.6t.

[0458] The construction section is divided by the centerline of the water diversion shaft, and the construction section of the upper bend section is 9m. Through CAD measurement, the calculated length of the concrete is l = 10.9m, the cross-sectional radius of the water diversion tunnel is 5m, the lining thickness is 0.8m, the over-excavation is 0.1m, and considering the partial coefficient of 1.4, the calculated concrete thickness is: h = (0.8 + 0.1) × 1.4 = 1.26m. To enhance the calculation safety and simplicity of the structure, the concrete thickness h = 1.3m is used for calculation.

[0459] When calculating the maximum pressure of newly poured concrete on the steel formwork, only the part above the center axis of the water diversion tunnel, that is, half of the concrete weight, is considered. Figure 46 As shown in the figure, when calculating the weight of the concrete above the central axis, considering that the weight of the concrete in the shaded area is borne by the poured concrete, the weight of the concrete is:

[0460] N′3=γS ABCD l=2.5×16.3×10.9=444.2t

[0461] Where: γ is the specific gravity of concrete, take γ=2.5t / m 3 ;S ABCD For the area of ​​quadrilateral ABCD, take S ABCD =16.3m 2

[0462] When calculating the standard value of concrete weight, the partial coefficient of 1.4 does not need to be considered. Only the lining thickness of 0.8m and the over-excavation of 0.1m are considered. At this time, the concrete thickness is 0.9m. The cross section at this time is as follows: Figure 47 As shown;

[0463] The standard values ​​for concrete weight are:

[0464] N3=γS ABCD l=2.5×0.9×11.6×10.9=284.49t

[0465] Where: γ is the specific gravity of concrete, take γ=2.5t / m 3 ;S ABCD For the area of ​​quadrilateral ABCD, take S ABCD =16.3m 2 , then the standard value of concrete weight is N3=284.5t;

[0466] The standard weight value of the upper bend section is: N = N1 + N2 + N3 = 15.4 + 53.0 + 284.5 = 352.9t

[0467] The design value of the weight of the upper bend is: N' = N'1 + N'2 + N'3 = 18.5 + 63.6 + 444.2 = 526.3t

[0468] Calculation of single vertical pole:

[0469] Calculate the load on a single pole by dividing the total weight by the number of poles:

[0470] from Figure 45 It can be seen that there are 13 rows of vertical poles in the actual calculation area, with 11 poles in each row, a total of n = 13 x 11 = 143 poles, and the load borne by each pole is F = N' / n = 526.3 / 143 = 3.68t;

[0471] Calculate the load using the ratio of the area occupied by a single pole to the actual area:

[0472] The distance between the poles is d = 0.75m, so the area occupied by a single pole is S1 = d 2 =0.75 2 =0.5625m 2 ,like Figure 48 As shown, there are n1 = 10 spacings in a row, and n2 = 12 spacings in a column, so the actual area is S2 = dn1 × dn2 = (0.75 × 10) × (0.75 × 12) = 67.5 m 2 ,like Figure 49 As shown, the load borne by a single vertical pole is:

[0473]

[0474] By comparing the calculation results of the two methods, the larger one is taken, so the load borne by a single vertical pole is calculated as F = 4.39t;

[0475] The specification of the vertical pole is a 48ⅹ3 round tube, and the material used is Q235 steel. The strength design value is f = 215Mpa. The vertical pole is calculated as an axially compressed member. The following will be verified from the two aspects of the vertical pole section strength and stability. In the following formula, σ is the calculated strength, F is the load on a single vertical pole, and A is the cross-sectional area of ​​the steel pipe, taking A = 423.9mm 2 , i is the radius of inertia, i x 、i y are the inertia radii of the x and y axes respectively, D is the outer diameter of the tube, which is D = 48 mm, d is the inner diameter of the tube, which is d = 48-2×3 = 42 mm, and λ x ,λ y are the slenderness ratios of the x and y axes, λ u To allow for slenderness ratio;

[0476] (1) Strength verification

[0477] Calculate in accordance with Article 7.1.2 of the Steel Structure Design Standard GB50017-2017.

[0478]

[0479] Safety factor:

[0480]

[0481] Meet the requirements.

[0482] (2) Stability verification

[0483] The effective height of the vertical pole is l = 1.2m, the cross-section type is class a, and the stability is calculated according to Article 7.2.1 of the "Steel Structure Design Standard GB50017-2017".

[0484] The radius of inertia of the tube is:

[0485]

[0486] The slenderness ratio of the vertical pole is:

[0487]

[0488] The slenderness ratio meets the requirements.

[0489] From the table, we can see that the stability coefficient is:

[0490]

[0491] The stability of the pole is:

[0492]

[0493] Meet the requirements.

[0494] Force on a single horizontal rod:

[0495] The horizontal rod mainly bears the lateral pressure generated by the concrete. The magnitude of the lateral pressure is calculated based on the pressure on one side. Here, P = 5.92t / m 2 Calculation. The spacing between vertical poles is d = 0.75m, and the spacing between horizontal poles is l = 1.2m. Figure 50 As shown, the area around a single horizontal rod is S3 = dl = 0.75 × 1.2 = 0.9 m 2 , the lateral pressure on a single horizontal rod is F 侧 =PS3=5.92×0.9=5.328t.

[0496] (1) Strength verification

[0497] The specification of the horizontal rod is a 48ⅹ3 round tube. According to Article 7.1.2 of the "Steel Structure Design Standard GB50017-2017", the parameters involved in the formula are the same as those of the vertical rod, and the meaning is the same:

[0498]

[0499] Safety factor:

[0500]

[0501] Meet the requirements.

[0502] (2) Stability verification

[0503] The effective length of the horizontal rod is l = 0.75m, and the radius of inertia is shown in Section 3.1.2.

[0504] The slenderness ratio of the horizontal rod is:

[0505]

[0506] The slenderness ratio meets the requirements.

[0507] From the table, we can see that the stability coefficient is:

[0508]

[0509] The stability of a horizontal rod is:

[0510]

[0511] Meet the requirements.

[0512] Strength and deflection verification of main and secondary beams:

[0513] Since the beam hinged at both ends will have greater bending moment and deflection at the mid-span, only the case of hinged at both ends is considered here.

[0514] Calculation of loads on main and secondary beams:

[0515] Since the main beam will bear 12 concentrated forces over the length of l1 = 3.162m, the magnitude of each concentrated force is F1 = 4.39 x 10 4 N, now the four concentrated forces are equivalent to uniformly distributed loads, the size of the uniformly distributed load is:

[0516]

[0517] Take the uniformly distributed load value of the main beam as q1=16.7ⅹ10 4 N / m;

[0518] Since the secondary beam will bear 4 concentrated forces over the length of l2 = 2.77m, the magnitude of each concentrated force is F2 = 4.39 x 10 4 N, now the four concentrated forces are equivalent to uniformly distributed loads, the size of the uniformly distributed load is:

[0519]

[0520] Take the uniformly distributed load value of the secondary beam as q2=6.34ⅹ10 4 N / m;

[0521] Calculation of maximum bending moment and deflection extreme values ​​of main and secondary beams:

[0522] The meanings of the parameters involved in the following formula are: M max Maximum bending moment, f max Maximum deflection, E is the elastic modulus of steel, I1 and I2 are the moments of inertia of the main and secondary beams respectively,

[0523] The maximum bending moment of the main beam is located at the mid-span, and its value is:

[0524]

[0525] The maximum deflection is also located at the mid-span position and its value is:

[0526]

[0527] The maximum bending moment of the secondary beam is at the mid-span, and its value is:

[0528]

[0529] The maximum deflection is also located at the mid-span position and its value is:

[0530]

[0531] Strength check:

[0532] The main and secondary beams are made of H-shaped steel of H300ⅹ300ⅹ12ⅹ12 and 22B I-shaped steel respectively. Since the main and secondary beams will bend and deform, the strength calculation of the main and secondary beams is carried out in accordance with Article 6.6.1 of the "Steel Structure Design Standard GB50017-2017". The calculation formula is as follows:

[0533]

[0534] Where: M x 、M y are the design values ​​of the bending moments around the x-axis and y-axis for the same section; W nx 、W ny are the net section moduli about the x-axis and y-axis,

[0535] γ x , γ y The cross-section plastic development coefficient shall be determined in accordance with Article 6.1.2 of the Steel Structure Design Standard GB50017-2017; f is the design value of the steel's flexural strength;

[0536] Since the section modulus of I-beam and H-beam on x and y axis is different, the section plastic development coefficient γ x , γ y Therefore, during construction, it is necessary to ensure that the I-beam is bent at the strong axis. Therefore, in the following calculation, only the strength at the strong axis is considered. At this time, γ x =1.05calculated.

[0537] (1) Main beam H300ⅹ300ⅹ12ⅹ12

[0538] According to Article 3.5.1 of the "Steel Structure Design Standard GB50017-2017", the flange plate of the H-shaped steel of H300ⅹ300ⅹ12ⅹ12 is S3 grade and the web plate is S1 grade. Therefore, there is no need to adjust the effective flange width to recalculate the section modulus. That is, the net section modulus of the H-shaped steel of H300ⅹ300ⅹ12ⅹ12 is the full interface modulus, which is W nx =1160cm 3 ;

[0539] The H-beam strength of the main beam H300ⅹ300ⅹ12ⅹ12 is:

[0540]

[0541] The safety factor is:

[0542]

[0543] (2) Secondary beam 22B I-beam

[0544] According to Article 3.5.1 of the "Steel Structure Design Standard GB50017-2017", the flange and web of 22B I-beam are both S1 grade, that is, when calculating the net section modulus of 22B I-beam, the full section modulus can be used instead. The section modulus at this time is W nx =325cm 3 ;

[0545] The strength of the secondary beam 22B I-beam is:

[0546]

[0547] The safety factor is:

[0548]

[0549] Meet the requirements.

[0550] Deflection check of main and secondary beams:

[0551] Deflection check is carried out according to the allowable deflection value of bending members in Appendix B.1 of the "Steel Structure Design Standard GB50017-2017".

[0552] The allowable deflection of the main beam is:

[0553]

[0554] The allowable deflection of the secondary beam is:

[0555]

[0556] Since the material used for the main and secondary beams is Q235 steel, according to Article 4.4.8 of the "Steel Structure Design Standard GB50017-2017", the elastic modulus E = 206GPa;

[0557] The meaning of each parameter in the following formula is: S1 is the area occupied by a single pole, and the size is S1 = 0.5625m 2 ; S2 is the actual area occupied by the scaffolding poles, which is S2 = 67.5m 2 ; N is the standard value of the total weight of the upper curved section, which is N = 352.9t; n1 and n2 are the number of concentrated forces on the main and secondary beams, respectively, which are n1 = 12 and n2 = 4; l1 and l2 are the lengths of the main and secondary beams, respectively;

[0558] (1) The maximum deflection of the H-beam of the main beam H300ⅹ300ⅹ12ⅹ12 is:

[0559]

[0560] The maximum deflection is:

[0561]

[0562] Meet the requirements.

[0563] (2) The standard load of the secondary beam 22B I-beam is:

[0564]

[0565] The maximum deflection is:

[0566]

[0567] Meet the requirements.

[0568] Step 5.2: Safety verification of the arch support of the lower bend section formwork:

[0569] The arch frame supporting the formwork of the lower bend section is divided into 10 frames, each weighing 108.135kg. The arch frames of the inclined arch section are arranged with a circumferential spacing of 1.0m. The arch frames processed in each hole are equipped with 11 frames according to the largest warehouse, and a total of 22 frames according to the two warehouse configuration. The CAD drawing size is as follows: Figure 51 As shown:

[0570] Finite element model establishment: In the abaqus finite element software, the beam unit is used to establish the model of the formwork support arch. The model is as follows Figure 52 As shown;

[0571] Set the material and section properties: the material used is Q235 steel, with a density of 7850kg / m 3 , the elastic modulus is 210GPa, and the Poisson's ratio is 0.3; the cross-sectional properties are given according to the construction drawings. The outer circle is No. 12 channel steel, the inner circle is I10 I-beam, and the inner and outer circles are connected by Φ48 steel pipes;

[0572] Analysis step setting and mesh unit division: The analysis step adopts the static general analysis step; the beam element adopts the B31 element provided by Abaqus;

[0573] Apply loads to the model:

[0574] The loads applied to the supporting arch are mainly (1) deadweight, which is calculated by the program, (2) deadweight of concrete within 1m width, which is 3.2t / m. (3) Lateral load, see step 2.3. Figure 53 As shown;

[0575] Model boundary conditions:

[0576] Apply constraints in the same direction as the lateral pressure at a node at the bottom of the model, and apply constraints in two directions different from the lateral pressure at other locations. The constraint arrangement of the starting template is as follows: Figure 54 shown.

[0577] Finite element calculation results:

[0578] Finite element calculation stress cloud diagram Figure 55 As shown, the maximum stress is 165.2MPa, while the allowable stress of Q235 steel is 215Mpa. The maximum stress is less than the allowable stress, so it meets the requirements.

[0579] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A design method for an intelligent trolley for the full-process integrated construction of a large-section, high-steep-slope inclined shaft, characterized by: The following steps are involved: Step 1: Calculation of trolley load, including: calculation of trolley deadweight load, calculation of concrete force on trolley, and calculation of trolley load on track; the calculation of trolley deadweight load includes calculation of trolley dead load and calculation of trolley live load, and the trolley dead load includes inner frame, needle beam, formwork, steel platform, walkway railing, lateral mechanical jack between single beam frame needle beam, anti-fall baffle, walking wheel, tail diagonal brace, stabilizer bar, middle diagonal brace, plumb cylinder guide column, connecting jack between formwork and single beam frame, high-end walking beam, high seat and cross connection, walkway pull rod and walking beam in formwork; the trolley live load includes working equipment, steel bars, and operators; the calculation of concrete force on trolley includes calculation of normal force, tangential force, and lateral force, where the tangential direction is parallel to the longitudinal centerline of the inclined shaft, and the normal direction is perpendicular to the 55-degree inclined plane; where the normal force of concrete on the trolley, the load perpendicular to the 55-degree inclined plane is: F 混 =(G 砼 )×cos55°, Where G 砼 is the actual weight of the concrete; The tangential force of concrete on the trolley is the tangential component of the concrete's own weight minus the support provided by the old concrete. The friction force parallel to the slope at all points on the cross section is calculated by integration to obtain the value of the overall friction force. Where: γ is the specific gravity of concrete, l is the pouring length, t is the pouring thickness, μ is the friction coefficient; R is the radius of the section, θ is the angle between [0, π], and V is the volume of concrete; The lateral pressure exerted by concrete on the formwork is: F=0.28r c t0β1β2V 0.5 , Where: r c is the deadweight of concrete; t0 is the initial setting time of concrete; β1 is the correction coefficient for the effect of admixtures, which is 1.0 when no admixtures are added and 1.2 when admixtures with retarding effect are added; β2 is the correction coefficient for the effect of slump, which is 0.85 when the slump is less than 30mm; 1.0 when the slump is 50-90mm; and 1.15 when the slump is 110-150mm; V is the pouring speed of concrete, which is V=1.5m / h; Step 2: Perform finite element analysis on the trolley, including: Step 2.1: Use ABAQUS, a finite element analysis software, to model each part of the trolley for stress analysis. The overall trolley model is split into a combined model of the template, inner frame, and needle beam. During modeling, the inner frame is modeled using beam elements, the template is modeled using shell elements, and the hydraulic jack connection between the template and inner frame is also modeled using beam elements. Step 2.2: Set material and section properties; Step 2.3: Apply loads to the model. The loads on the trolley include: the trolley's own weight calculated by the ABAQUS software program, the tangential force and normal force of the concrete, the uniformly distributed load applied to the upper semicircular surface of the trolley formwork, and the lateral load. Step 2.4: Analysis step setting and mesh element division; Step 3: Calculation and review of trolley safety; Step 4: Track safety calculation and review, including: Step 4.1: Anchor bolt calculation and verification: Use the embedded parts method or through-wall bolt method to calculate the anchor bolt stress under both walking and pouring conditions; verify the strength of the concrete around the anchor bolt. Step 4.2: Calculate and verify the slot, calculate and verify the safety under the running condition and pouring condition respectively; Step 4.3: Verify the concrete stress under the track cushion; Step 4.4: Calculate and verify the track base plate, including the shear resistance verification of the track base plate bolts and the weld verification of the track base plate lugs; Step 5: Calculation and review of the safety of the curved section structure, including: Step 5.1: Calculation and verification of the upper bend section: The calculation and verification of the upper bend section revolve around the design and safety verification of the scaffolding, including the safety verification of the vertical poles, horizontal poles, main and secondary beams; Step 5.2: Verify the safety of the arch frame supported by the formwork in the lower bend section.

2. The method for designing an intelligent trolley for the integrated construction of a large-section, high-steep-slope inclined shaft according to claim 1 is characterized in that: In step 4.1, the through-wall bolt method is used for calculation, including the calculation of the design value of the bearing capacity of each bolt under shear alone: Where, is the design value of the bolt shear strength; D is the bolt rod diameter.

3. The method for designing an intelligent trolley for the integrated construction of a large-section, high-steep-slope inclined shaft according to claim 1 is characterized in that: In the step 4.2: slot calculation and verification, the calculations for both the walking condition and the pouring condition include local compression resistance verification and shear resistance verification.

4. The method for designing an intelligent trolley for the integrated construction of a large-section, high-steep-slope inclined shaft according to claim 1 is characterized in that: In the step 4.4: track base plate calculation and review, the bolts used in the shear resistance verification of the track base plate bolts are M20, each base plate has 6 bolts, and in the weld verification at the track base plate ear plate, each base plate has 4 plates fixed with welds.

5. The method for designing an intelligent trolley for the integrated construction of a large-section, high-steep-slope inclined shaft according to claim 1 is characterized in that: In the step 2.4: setting the analysis step and dividing the mesh element, the analysis step adopts the static general analysis step; the beam element adopts the B31 element provided by ABAQUS, and the shell element adopts the S4R element provided by ABAQUS for mesh division.

6. The method for designing an intelligent trolley for the integrated construction of a large-section, high-steep-slope inclined shaft according to claim 1 is characterized in that: In the step 3: trolley safety calculation and review, the trolley is divided into six parts: needle beam module, inner frame module, template module, diagonal support module, stabilizer rod component, and pin shaft component.

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