A construction access road structure and construction method in tidal flat areas

Abstract

The present invention discloses a construction access road structure and construction method on a tidal flat, including an emulsified asphalt seal layer, a crushed stone layer, a sand cushion layer, a geogrid sandwiched in the sand cushion layer and a multi-section roadbed box, which are sequentially laid on the solidified soil of the soft soil foundation in the tidal flat mud zone. The multi-section roadbed box is laid longitudinally along the construction access road, and the ends of each two adjacent sections of the roadbed box are connected to each other by a plurality of concave and convex grooves in the horizontal direction to form a continuous construction access road surface. The structure has the following advantages: first, it is low in cost and is beneficial to the protection of the marine ecological environment; second, the top surface of the solidified soil adopts a non-stick wheel emulsified asphalt seal layer, which plays a waterproof role, reduces the damage of the sticky layer during construction, improves the bonding force with the solidified soil, and significantly improves the ability and durability of preventing seawater from penetrating and corroding the steel roadbed box; third, the provided calculation method has a clear principle, is practical and easy to implement, improves the safety and quality performance of the project, and brings higher economic and social benefits.

Description

Technical Field

[0001] The invention relates to a construction access road structure, in particular to a construction access road structure on a tidal flat area and a construction method. Background Art

[0002] When constructing roads and bridges along the coast, it is often necessary to build construction access roads in muddy and muddy areas. Since the soil in muddy and muddy areas has a high moisture content, high compressibility, and low bearing capacity, the traditional method of building construction access roads is to fill thick sand and gravel fillers and harden concrete. Not only does it require a large amount of materials, it is heavy, causes a large load on the base, and is expensive, but it is also not conducive to the protection of the marine ecological environment. In recent years, a simple roadbed with solidified soil in muddy and muddy areas has been used to lay a reused steel roadbed box as a construction access road. However, due to the large load of vehicles passing through the construction access road, under the action of heavy vehicle loads and additional vibration forces, the simple roadbed at the bottom of the roadbed box often becomes partially empty, resulting in a reduction in the bearing capacity of the roadbed box, while aggravating the damage to the simple roadbed, so that a new roadbed box needs to be replaced or even the construction access road needs to be repaired. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a construction access road structure and construction method on tidal flat mud areas which are simple in structure, safe and reliable, convenient in construction, scientific in maintenance, and low in carbon and environmentally friendly.

[0004] The technical problem of the present invention is achieved through the following technical solutions:

[0005] A construction access road structure on a tidal flat area comprises a soft soil foundation in a tidal flat mud area and solidified soil on the soft soil foundation, wherein an emulsified asphalt seal layer, a crushed stone layer, a sand cushion layer, a geogrid sandwiched in the sand cushion layer and a multi-section roadbed box are sequentially laid layer by layer on the solidified soil, wherein the multi-section roadbed boxes are laid longitudinally along the construction access road, and the ends of each two adjacent sections of the roadbed boxes are laterally connected to each other by a plurality of concave and convex grooves to form a continuous construction access road surface.

[0006] The subgrade box described above produces partial hollowing of the bottom of the subgrade box under the action of vehicle loads, and any three sections of subgrade boxes laid longitudinally along the construction access road are used to analyze the hollowing of the simple subgrade at the bottom of the subgrade box. The middle section of the subgrade box is subjected to vehicle loads, and the vehicle load is converted into a uniformly distributed load q including vibration and impact forces. The simple subgrade within the span 2a where the subgrade box is subjected to the greatest force undergoes uneven settlement, causing partial hollowing of the bottom of the subgrade box. The subgrade box is regarded as an elastic foundation beam. Due to the large bending stiffness of the subgrade box, the geogrid does not participate in the force calculation and only plays a role in dispersing the load. The effect of roadbed box pressure, according to the elastic foundation beam theory, assume that the endpoints C of the other two roadbed boxes far from the middle roadbed box are free ends without shear force and bending moment, the middle roadbed box and its adjacent roadbed box end are connected by multiple concave and convex grooves in the horizontal direction. The B end is hinged, and the vehicle load is transmitted through shear force. The vertical displacement of the two roadbed boxes at the hinge of the B end of the adjacent roadbed box end is the same. The vertical displacement, rotation angle, bending moment and shear force of the three roadbed boxes as elastic foundation beams under the action of vehicle load are calculated as follows:

[0007] Formula 1:

[0008]

[0009] The solution is:

[0010]

[0011] Formula 2:

[0012] AB segment:

[0013]

[0014] The solution is:

[0015]

[0016] Formula 3:

[0017] BC segment:

[0018]

[0019]

[0020] Formula 4:

[0021] The boundary conditions and continuity conditions of the three roadbed boxes are:

[0022] (1) Point O:

[0023] (2) Point A:

[0024] (3) Point B:

[0025] (4) Point C:

[0026] According to the above boundary conditions and continuity conditions of the three-section roadbed box, the coefficients to be determined can be solved by formula 1, formula 2 and formula 3 respectively ,have to

[0027]

[0028] If the three sections of roadbed boxes are all subjected to vehicle loads, the superposition method is used for calculation. The local empty range 2a of the roadbed box bottom is measured by geological radar. The stress condition of the roadbed box is calculated by the above method. If the stress of the roadbed box reaches a critical state, the roadbed box is removed to repair the empty roadbed and lay the roadbed box again. If the calculation result is too different from the measured data, five sections of the roadbed box are taken for calculation according to the above method.

[0029] The symbols in Formula 1, Formula 2 and Formula 3 are defined as:

[0030] ——Uniformly distributed vehicle load including vibration and impact force, its value is , ;

[0031] ——Foundation reaction coefficient, determined by test or by checking relevant specifications, ;

[0032] ——Characteristic coefficient, a comprehensive parameter related to the elastic properties of the roadbed box and foundation, reflecting the relative stiffness of the foundation and foundation beam;

[0033] ——half of the length of the local hollow space at the bottom of the middle section of the roadbed box, ;

[0034] ——Average moment of inertia of roadbed box section, ;

[0035] ——Elastic modulus of roadbed box material, ;

[0036] ——Undetermined coefficient;

[0037] ——Respectively The number of the maximum bending moment and maximum shear force of the segment, ;

[0038] ——Respectively The foundation reaction of the segment, ;

[0039] —— respectively, the center of the position where the bottom of the middle roadbed box is partially empty (8) Roadbed box with point as origin The vertical deformation curve equation of the segment, the roadbed box with the starting point A of the non-empty segment as the origin The vertical deformation curve equation of the segment, the roadbed box with point B as the origin The vertical deformation curve equation of the segment is: ;

[0040] ——Respectively point, point, The point is the vertical and horizontal coordinate value of the origin. ;

[0041] ——Respectively roadbed box part, part, Any cross-section angle of the segment, ;

[0042] ——Respectively roadbed box part, part, Bending moment at any section of the segment, ;

[0043] ——Respectively roadbed box part, part, The maximum bending moment of the segment, ;

[0044] ——Separate roadbed boxes part, part, Shear force at any section of the segment, ;

[0045] ——Respectively roadbed box part, part, The maximum shear force of the segment, ;

[0046] ——The connecting shear force of multiple transverse concave and convex grooves between one end of the middle roadbed box and the adjacent roadbed box, ;

[0047] ——Permissible bending moment of roadbed box, ;

[0048] - allowable shear force of the roadbed box, .

[0049] The roadbed box is a rectangular steel box body welded by a top plate, a longitudinal beam, a cross beam and a bottom plate. Each section is 5m long and 4m wide, and 20cm to 30cm thick. The longitudinal beams and cross beams are I-beams. The top plate and the bottom plate are steel plates with a thickness of 10mm to 15mm, and a V-shaped anti-slip strip is welded on the surface of the top plate. The overall and component sizes of the roadbed box are determined according to the width of the construction access road, the load to be borne and the bearing capacity of the soft soil foundation.

[0050] Holes are reserved at the four corners of the roadbed box, and pins are driven in as positioning components after paving is completed.

[0051] The two ends of each section of the roadbed box are laterally provided with a plurality of convex slots and a plurality of concave slots. When splicing, the convex slots and concave slots corresponding to each two adjacent sections of the roadbed box are butted and engaged with each other and then fixed with bolts.

[0052] The stabilized soil is a soil that utilizes a series of physical-chemical reactions between a curing agent and soft soil to harden the soft soil into a foundation soil with integrity, water stability and a certain strength. The 7d unconfined compressive strength of the stabilized soil is not less than 3MPa.

[0053] The emulsified asphalt seal is a seal in which the non-stick wheel emulsified asphalt is sprayed on the top surface of the solidified soil.

[0054] The crushed stone layer is the main load-bearing structure of the simple roadbed of the construction access road. It is composed of graded crushed stone with a crushed stone particle size of less than 4 cm, a mud content of less than 3%, a thickness of 50 cm to 100 cm, and a compaction degree of not less than 80%; the sand cushion layer is medium-coarse sand, with a mud content of less than 3% and a thickness of 3 cm to 5 cm.

[0055] The geogrid is a steel-plastic geogrid.

[0056] A construction method for a construction access road structure on a tidal flat mud zone comprises the following steps:

[0057] Step 1: Draft a construction access road structure plan on the mudflat area

[0058] According to the construction loads borne by the construction access road, geological drilling data and design drawings, the selection of roadbed box and the thickness and technical indicators of geogrid, sand cushion, crushed stone layer, emulsified asphalt seal layer and solidified soil are formulated;

[0059] ② Calculate the maximum empty length 2a of the roadbed box bottom and the corresponding deformation and internal force through formula 1 to formula 3;

[0060] Step 2: Solidification of soil

[0061] ①Remove impurities from the surface of the treatment area;

[0062] ②Backfill and level the soft soil according to the designed solidified soil top elevation, and conduct on-site trial mixing before construction. If the mixing head itself is difficult to mix the sinking soil layer, first excavate the soil layer as a whole or partially, and then carry out solidification construction after excavation and rough leveling;

[0063] ③ Divide the construction area into blocks and divide them into treatment areas with a size of 5m×5m or 5m×6m;

[0064] ④ Calculate the amount of curing agent according to the soft soil engineering volume of the treatment section, use the curing agent automatic quantitative feeding system to set the curing agent spraying rate, and install the curing agent addition control system in the background feeding system to control the amount of curing agent added in real time, accurately measure, reduce material waste, and record and save the curing agent dosage process in real time to form a report;

[0065] The mixing equipment is directly inserted to mix the in-situ soil;

[0066] The mixing equipment runs forward to gradually mix and spray the curing agent until it reaches the bottom of the curing design;

[0067] The mixing equipment runs in reverse, slowly lifts and stirs and sprays the curing agent. The stirring lifting or lowering rate is controlled at 10s / m~20s / m, and the curing agent spraying rate is controlled at 80kg / min~150kg / min. The specific rate is adjusted accordingly according to the actual operation conditions on site to ensure uniform spraying and stirring during the construction process;

[0068] After the solidification construction is completed, the construction area is leveled and the surface is compacted to ensure the integrity of the board and the compaction of the surface soil. The solidified soil is cured for more than 7 days and natural curing is adopted. In case of rainy days, plastic film is laid on the surface of the solidification site, and the drainage of the site is strengthened to reduce the impact of rainwater.

[0069] Step 3: Construction of emulsified asphalt seal layer, crushed stone layer, sand cushion layer and geogrid

[0070] ① Clear the loose soil and debris on the solidified soil base, lay out the center line and side line of the leveling layer, and set up indicator stakes at the edges of the shoulders on both sides for measurement and layout. The elevation is measured with a level;

[0071] ② Spray the non-stick wheel emulsified asphalt seal layer on the top surface of the solidified soil. The amount of non-stick wheel emulsified asphalt sprayed is converted into pure asphalt dosage of 0.35kg / m2~0.45kg / m2. The seal layer should be sprayed evenly;

[0072] ③ Spread the crushed stone evenly on the non-stick wheel emulsified asphalt seal layer of the predetermined width, with each layer of 20cm to 30cm, and compact it layer by layer with a light roller;

[0073] ④ The sand cushion is spread twice, the first layer is 1cm~2cm, the geogrid is laid on the first sand cushion and flattened, the corners are fixed with soil nails, the geogrid joints overlap, and the overlapping width is 50cm~100cm;

[0074] ⑤ Spread the second layer of sand cushion 1cm to 2cm on the geogrid and use a light roller to flatten it;

[0075] Step 4: Hoisting the roadbed box

[0076] Use a crane to lay the first section of the roadbed box that has passed the inspection longitudinally along the construction access road, drive steel pins into the reserved holes at the four corners of the roadbed box, fasten the top of the pins to the top plate of the roadbed box with fasteners, and require accurate positioning;

[0077] Use a crane to hoist the second section of the roadbed box, and connect the multiple convex grooves at one end of the second section of the roadbed box with the multiple concave grooves corresponding to one end of the laid first section of the roadbed box, and then fix them with bolts;

[0078] ③ Splice all longitudinal roadbed boxes in the above order. If it is a double-lane construction access road, lay the roadbed boxes on the other lane in the same order;

[0079] ④ Set up horizontal displacement and settlement observation points at appropriate locations of the completed roadbed box, conduct the first observation and record;

[0080] ⑤ Use geological radar to detect the contact between the completed roadbed box and the sand cushion layer as comparative data for the use stage;

[0081] Step 5: Use and maintain

[0082] After the construction of the roadbed box construction access road is completed, the horizontal displacement, vertical settlement and the bottom of the roadbed box are regularly detected with a total station and a geological radar, the dynamics of the use of the roadbed box construction access road are mastered, and the data on whether the bottom of the roadbed box is empty is determined. If the roadbed box sways or jumps, it should be detected in time with a total station and a geological radar;

[0083] If the extent of the roadbed box being empty reaches a critical value, the roadbed box will be dismantled, repaired, and then the roadbed box will be laid again and put back into use.

[0084] Compared with the prior art, the present invention provides a construction access road structure on a tidal flat area, wherein the structure comprises an emulsified asphalt seal layer, a crushed stone layer, a sand cushion layer, a geogrid sandwiched in the sand cushion layer, and a multi-section roadbed box which are sequentially laid on the solidified soil of the soft soil foundation in the tidal flat mud area. The multi-section roadbed boxes are laid longitudinally along the construction access road, and the ends of each two adjacent sections of the roadbed boxes are laterally connected to each other by a plurality of concave and convex grooves to form a continuous construction access road surface. The construction access road structure has the following advantages: first, it is set to overcome the traditional construction access road construction method of building sand and gravel fillers and concrete hardening on coastal tidal flats, which is low in cost and beneficial to the protection of marine ecological environment; second, the top surface of the solidified soil adopts a non-stick wheel emulsified asphalt seal layer, which plays a waterproof role, reduces the damage of the sticky layer during construction, improves the adhesion with the solidified soil, and significantly improves the ability and durability of preventing seawater from penetrating and corroding the steel roadbed box; third, the calculation method provided is clear in principle, practical and easy to implement, and can be used as a technical guide for the construction and use and maintenance of the roadbed box construction access road on the tidal flat through the monitoring and control of the geological radar, thereby improving the safety and quality performance of the project. Therefore, the construction access road structure on the tidal flat of the present invention has the advantages of simple structure, safety and reliability, convenient construction, scientific maintenance, low carbon and environmental protection, etc., and it can bring higher economic and social benefits in combination with the corresponding operation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention.

[0086] Figure 2 This is a schematic diagram of the structure of the roadbed box.

[0087] Figure 3 This is the force calculation diagram for the partial void at the bottom of the roadbed box. DETAILED DESCRIPTION

[0088] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0089] like Figure 1~Figure 3 As shown, 1. soft soil foundation, 2. solidified soil, 3. emulsified asphalt seal layer, 4. crushed stone layer, 5. sand cushion layer, 6. geogrid, 7. roadbed box, 71. longitudinal beam, 72. cross beam, 73. top plate, 74. bottom plate, 75. latch, 76. convex slot, 77. concave slot, 8. partial hollowing.

[0090] A construction access road structure and construction method on a tidal flat zone, comprising a soft soil foundation 1 in a tidal flat mud zone and solidified soil 2 on the soft soil foundation, wherein an emulsified asphalt seal layer 3, a crushed stone layer 4, a sand cushion layer 5, a geogrid 6 sandwiched in the sand cushion layer, and a multi-section roadbed box 7 are sequentially laid layer by layer on the solidified soil, and the multi-section roadbed boxes are laid longitudinally along the construction access road, and the ends of each two adjacent sections of the roadbed boxes 7 are connected to each other by a plurality of concave and convex grooves in the transverse direction to form a continuous construction access road surface.

[0091] Among them, the soft soil foundation 1 is soft soil in the tidal flat mud zone, which has the characteristics of high soil moisture content, high compressibility and low bearing capacity, while the solidified soil 2 utilizes a series of physical and chemical reactions produced between the curing agent and the soft soil to harden the soft soil into foundation soil with integrity, water stability and certain strength. The 7d unconfined compressive strength of the solidified soil 2 is not less than 3MPa.

[0092] The emulsified asphalt seal layer 3 is a seal layer of non-stick wheel emulsified asphalt sprayed on the top surface of the solidified soil 2, which plays a waterproof role and prevents seawater from penetrating and corroding the steel roadbed box. The non-stick wheel emulsified asphalt has a fast curing speed and a fast demulsification speed. It can be demulsified within 10 minutes, which can significantly improve the construction efficiency; it can reach 60°C non-stick wheel, and is not easily carried away by construction vehicles during construction. No need to re-spray, improve the spreading effect of non-stick wheel emulsified asphalt, reduce the damage of the sticky layer during construction, improve the adhesion with the solidified soil, and significantly improve the ability and durability to prevent seawater penetration.

[0093] The crushed stone layer 4 is the main load-bearing structure of the simple roadbed of the construction access road, and is composed of graded crushed stones with a crushed stone particle size of less than 4 cm, a mud content of less than 3%, a thickness of 50 cm to 100 cm, and a compaction degree of not less than 80%.

[0094] The sand cushion layer 5 is medium-coarse sand, has a mud content of less than 3%, and a thickness of 3 cm to 5 cm.

[0095] The geogrid 6 is a steel-plastic geogrid.

[0096] The roadbed box 7 is a steel rectangular box body, which is welded by a top plate 73, a longitudinal beam 71, a cross beam 72, and a bottom plate 74. It is customized by a professional manufacturer. The general specifications are that each section is 5m long × 4m wide and 20cm to 30cm thick. The longitudinal beam 71 and the cross beam 72 are both I-beams, and the top plate 73 and the bottom plate 74 are both steel plates with a thickness of 10mm to 15mm. A V-shaped anti-skid strip is welded on the surface of the top plate 73 to prevent the vehicle tires from slipping. The overall and component sizes of the roadbed box 7 are determined according to the width of the construction access road, the load required to be borne, and the bearing capacity of the soft soil foundation.

[0097] Holes are reserved at the four corners of the roadbed box 7, and steel pins 75 are driven in as positioning components after paving is completed.

[0098] A slot-type joint is provided between each section of the roadbed box 7. A plurality of convex slots 76 and a plurality of concave slots 77 are transversely provided at both ends of each section of the roadbed box 7. When splicing, the convex slots 76 and the concave slots 77 corresponding to each two adjacent sections of the roadbed box 7 are butted and fitted together, and then fixed with bolts, which can effectively prevent the roadbed boxes 7 from being offset or separated from each other.

[0099] The local hollowing 8 refers to the uneven sinking of the simple roadbed at the bottom of the roadbed box 7 under the action of heavy vehicle load and additional vibration force, which causes the roadbed box to be partially hollowed out 8, resulting in a reduction in the bearing capacity of the roadbed box and aggravated damage to the simple roadbed, so that a new roadbed box needs to be replaced or even the construction access road needs to be repaired.

[0100] The roadbed box 7 of the present invention produces partial hollowing of the bottom of the roadbed box under the action of vehicle load, and the hollowing of the simple roadbed at the bottom of the roadbed box is analyzed by any three sections of roadbed boxes laid longitudinally along the construction access road. The middle section of the roadbed box is subjected to the vehicle load, and the vehicle load is converted into a uniformly distributed load q including vibration and impact force. The simple roadbed within the span 2a range where the roadbed box 7 is subjected to the greatest force undergoes uneven settlement, causing partial hollowing of the bottom of the roadbed box. The roadbed box is regarded as an elastic foundation beam. Due to the large bending stiffness of the roadbed box, the geogrid 6 does not participate in the force calculation and only plays a role To disperse the pressure of the roadbed box, according to the elastic foundation beam theory, it is assumed that the endpoints C of the other two roadbed boxes far from the middle roadbed box are free ends without shear force and bending moment. The B end of the middle roadbed box connected to the adjacent roadbed box end with multiple concave and convex grooves is hinged, and the vehicle load is transmitted through shear force. The vertical displacement of the two roadbed boxes at the hinge of the B end of the adjacent roadbed box end with multiple concave and convex grooves is the same. The vertical displacement, rotation angle, bending moment and shear force calculation formula of the three roadbed boxes as elastic foundation beams under the action of vehicle load are as follows:

[0101] Formula 1:

[0102]

[0103] The solution is:

[0104]

[0105] Formula 2:

[0106] AB segment:

[0107]

[0108] The solution is:

[0109]

[0110] Formula 3:

[0111] BC segment:

[0112]

[0113]

[0114] Formula 4:

[0115] The boundary conditions and continuity conditions of the three-section roadbed box 7 are as follows:

[0116] (1) Point O:

[0117] (2) Point A:

[0118] (3) Point B:

[0119] (4) Point C:

[0120] According to the above boundary conditions and continuity conditions of the three-section roadbed box 7, the coefficients to be determined can be solved by formula 1, formula 2 and formula 3 respectively. ,have to

[0121]

[0122] If the three sections of roadbed boxes 7 are all subjected to vehicle load, the superposition method is used for calculation, and the local hollow 8 range 2a of the bottom of the roadbed box is measured by geological radar. The stress condition of the roadbed box is calculated by the above method. If the stress of the roadbed box reaches a critical state, the roadbed box is removed to repair the hollow roadbed and lay the roadbed box again. If the calculation result differs too much from the measured data, five sections of the roadbed box are taken for calculation according to the above method;

[0123] The symbols in Formula 1, Formula 2 and Formula 3 are defined as:

[0124] ——Uniformly distributed load of vehicle load including vibration and impact force, its value is , ;

[0125] ——Foundation reaction coefficient, determined by test or by checking relevant specifications, ;

[0126] - Characteristic coefficient, a comprehensive parameter related to the elastic properties of the roadbed box 7 and the foundation, reflecting the relative stiffness of the foundation and the foundation beam;

[0127] ——half of the length of the local hollow space at the bottom of the middle section of the roadbed box, ;

[0128] ——Average moment of inertia of the roadbed box 7 section, ;

[0129] ——Elastic modulus of roadbed box 7 material, ;

[0130] ——Undetermined coefficient;

[0131] ——Respectively The number of the maximum bending moment and maximum shear force of the segment, ;

[0132] ——Respectively The foundation reaction of the segment, ;

[0133] ——The middle roadbed box bottom is partially empty at 8 positions. Roadbed box with point as origin The vertical deformation curve equation of the segment, the roadbed box with the starting point A of the non-empty segment as the origin The vertical deformation curve equation of the segment, the roadbed box with point B as the origin The vertical deformation curve equation of the segment is: ;

[0134] ——Respectively point, point, The point is the vertical and horizontal coordinate value of the origin. ;

[0135] ——Respectively roadbed box part, part, Any cross-section angle of the segment, ;

[0136] ——Respectively roadbed box part, part, Bending moment at any section of the segment, ;

[0137] ——Respectively roadbed box part, part, The maximum bending moment of the segment, ;

[0138] ——Separate roadbed boxes part, part, Shear force at any section of the segment, ;

[0139] ——Respectively roadbed box part, part, The maximum shear force of the segment, ;

[0140] ——The connecting shear force of the transverse concave and convex grooves between one end of the middle roadbed box 7 and the adjacent roadbed box, ;

[0141] ——Permissible bending moment of roadbed box 7, ;

[0142] —— allowable shear force of roadbed box 7, .

[0143] At the same time, the construction method of the access road structure on the tidal flat mud zone mainly includes the following steps:

[0144] Step 1: Draft a construction access road structure plan on the mudflat area

[0145] According to the construction load borne by the construction access road, geological drilling data and design drawings, the selection of the roadbed box and the thickness and technical indicators of the geogrid 6, sand cushion layer 5, crushed stone layer 4, emulsified asphalt seal layer 3, and solidified soil 2 are formulated;

[0146] ② Calculate the maximum empty length 2a of the roadbed box bottom and the corresponding deformation and internal force through formula 1 to formula 3;

[0147] Step 2: Solidification of soil

[0148] ① Remove impurities on the surface of the treatment area and other debris that may affect the sinking and mixing of the solidified soil during construction;

[0149] ②Backfill and level the soft soil according to the designed solidified soil top elevation 2, and conduct on-site trial mixing before construction. If the mixing head itself is difficult to mix the sinking soil layer, first excavate this part of the soil layer as a whole or partially, and then carry out solidification construction after excavation and rough leveling;

[0150] ③ Divide the construction area into blocks and divide them into treatment areas with a size of 5m×5m or 5m×6m;

[0151] ④ Calculate the amount of curing agent according to the soft soil engineering volume of the treatment section, use the curing agent automatic quantitative feeding system to set the curing agent spraying rate, and install the curing agent addition control system in the background feeding system to control the amount of curing agent added in real time, accurately measure, reduce material waste, and record and save the curing agent dosage process in real time to form a report;

[0152] The mixing equipment is directly inserted to mix the in-situ soil;

[0153] The mixing equipment runs forward to gradually mix and spray the curing agent until it reaches the bottom of the curing design;

[0154] The mixing equipment runs in reverse, slowly lifts and stirs and sprays the curing agent. The stirring lifting or lowering rate is controlled at 10s / m~20s / m, and the curing agent spraying rate is controlled at 80kg / min~150kg / min. The specific rate is adjusted accordingly according to the actual operation conditions on site to ensure uniform spraying and stirring during the construction process;

[0155] After the solidification construction is completed, the construction area is leveled and the surface is compacted by excavators and other machinery to ensure the integrity of the board and the compaction of the surface soil. The solidified soil is cured for more than 7 days and natural curing is adopted. In case of rainy days, plastic film is laid on the surface of the solidification site, and the drainage of the site is strengthened to reduce the impact of rainwater.

[0156] Step 3: Construction of emulsified asphalt seal layer, crushed stone layer, sand cushion layer and geogrid

[0157] ① Clear the loose soil and debris on the solidified soil 2 base surface, lay out the center line and side line of the leveling layer, and set up indicator stakes at the edges of the shoulders on both sides for measurement and layout. The elevation is measured with a level;

[0158] ② Spray 3 layers of non-stick emulsified asphalt seal on the top surface of the solidified soil. The amount of non-stick emulsified asphalt spread is converted into pure asphalt dosage of 0.35kg / m2~0.45kg / m2. The seal should be sprayed evenly;

[0159] ③ Spread the crushed stone evenly on the non-stick wheel emulsified asphalt seal layer of the predetermined width, with each layer of 20cm to 30cm, and compact it layer by layer with a light roller;

[0160] ④ The sand cushion layer 5 is spread twice, the first layer is 1cm to 2cm, the geogrid 6 is laid on the first sand cushion layer and flattened, the corners are fixed with soil nails, the geogrid joints overlap, and the overlapping width is 50cm to 100cm;

[0161] ⑤ Spread the second layer of sand cushion 1cm to 2cm on the geogrid 6 and use a light roller to flatten it;

[0162] Step 4: Hoisting the roadbed box

[0163] Use a crane to lay the first section of the roadbed box that has passed the inspection longitudinally along the construction access road, and drive steel pins 75 into the reserved holes at the four corners of the roadbed box 7. Fasten the top of the pin to the top plate of the roadbed box with fasteners, and require accurate positioning;

[0164] Use a crane to hoist the second section of the roadbed box, and mate the multiple convex grooves 76 at one end of the second section of the roadbed box with the multiple concave grooves 77 corresponding to one end of the laid first section of the roadbed box, and then fix them with bolts;

[0165] ③ Splice all longitudinal roadbed boxes in the above order. If it is a double-lane construction access road, lay the roadbed boxes on the other lane in the same order;

[0166] ④ Set up horizontal displacement and settlement observation points at appropriate locations of the completed roadbed box 7, conduct the first observation and record;

[0167] ⑤ Use geological radar to detect the contact between the completed roadbed box and the sand cushion layer as comparative data for the use stage;

[0168] Step 5: Use and maintain

[0169] After the construction of the roadbed box construction access road is completed, the horizontal displacement, vertical settlement and the bottom of the roadbed box are regularly detected with a total station and a geological radar, the dynamics of the use of the roadbed box construction access road are mastered, and the data on whether the bottom of the roadbed box is empty is determined. If the roadbed box sways or jumps, it should be detected in time with a total station and a geological radar;

[0170] If the extent of the roadbed box being empty reaches a critical value, the roadbed box will be dismantled, repaired, and then the roadbed box will be laid again and put back into use.

[0171] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design similar to this embodiment should be included in the protection scope of the present invention.

Claims

1. A construction access road structure on a tidal flat, comprising a soft soil foundation (1) in a tidal flat muddy area and solidified soil (2) on the soft soil foundation, characterized in that An emulsified asphalt seal layer (3), a crushed stone layer (4), a sand cushion layer (5), a geogrid (6) sandwiched in the sand cushion layer, and a multi-section roadbed box (7) are sequentially laid on the solidified soil. The multi-section roadbed boxes are laid along the longitudinal direction of the construction access road. The ends of each two adjacent sections of the roadbed boxes (7) are connected to each other by a plurality of concave and convex grooves in the transverse direction to form a continuous construction access road surface. The roadbed box (7) produces a partial hollowing out (8) at the bottom of the roadbed box under the action of vehicle loads. Any three sections of the roadbed boxes laid along the longitudinal direction of the construction access road are used to analyze the hollowing out of the simple roadbed at the bottom of the roadbed box. The middle section of the roadbed box (7) is subjected to the action of vehicle loads. The vehicle load is converted into a uniformly distributed load q including vibration and impact forces. The maximum force on the roadbed box is within the mid-span 2a range. The simple roadbed undergoes uneven settlement, causing the bottom of the roadbed box to be partially emptied. The roadbed box is regarded as an elastic foundation beam. Since the roadbed box (7) has a large bending stiffness, the geogrid (6) does not participate in the force calculation and only plays a role in dispersing the pressure of the roadbed box. According to the elastic foundation beam theory, it is assumed that the endpoints C of the other two roadbed boxes far from the middle roadbed box are free ends without shear force and bending moment. The middle roadbed box and its adjacent roadbed box end are connected by multiple concave and convex grooves in the horizontal direction. The B end is hinged to transmit vehicle loads through shear force. The vertical displacements of the two roadbed boxes at the hinge of the B end of the adjacent roadbed box end are the same. The vertical displacement, rotation angle, bending moment and shear force of the three roadbed boxes as elastic foundation beams under the action of vehicle loads are calculated as follows: Formula 1: The solution is: Formula 2: AB segment: The solution is: Formula 3: BC segment: Formula 4: The boundary conditions and continuity conditions of the three-section roadbed box (7) are: ⑴O point: (2) Point A: ⑶B point: (4) Point C: According to the above boundary conditions and continuity conditions of the three-section roadbed box (7), the coefficients to be determined can be solved by formula 1, formula 2 and formula 3 respectively: ,have to If the three sections of roadbed boxes (7) are all subjected to vehicle load, the superposition method is used for calculation. The local void (8) of the bottom of the roadbed box has a range of 2a measured by geological radar. The stress condition of the roadbed box is calculated by the above method. If the stress of the roadbed box reaches a critical state, the roadbed box is removed to repair the voided roadbed and the roadbed box is laid again. If the calculated result differs too much from the measured data, five sections of the roadbed box are taken for calculation according to the above method. The symbols in Formula 1, Formula 2 and Formula 3 are defined as: ——Uniformly distributed load of vehicle load including vibration and impact force, its value is , ; ——Foundation reaction coefficient, determined by test or by checking relevant specifications, ; - Characteristic coefficient, a comprehensive parameter related to the elastic properties of the roadbed box (7) and the foundation, reflecting the relative stiffness of the foundation and the foundation beam; ——half of the length of the local hollow space at the bottom of the middle section of the roadbed box, ; ——Average moment of inertia of the roadbed box (7) section, ; ——Elastic modulus of the roadbed box (7) material, ; ——Undetermined coefficient; ——Respectively The number of the maximum bending moment and maximum shear force of the segment, ; ——Respectively The foundation reaction of the segment, ; —— respectively, the center of the position where the bottom of the middle roadbed box is partially empty (8) Roadbed box with point as origin The vertical deformation curve equation of the segment, the roadbed box with the starting point A of the non-empty segment as the origin The vertical deformation curve equation of the segment, the roadbed box with point B as the origin The vertical deformation curve equation of the segment is: ; ——Respectively point, point, The point is the vertical and horizontal coordinate value of the origin. ; ——Respectively roadbed box part, part, Any cross-section angle of the segment, ; ——Respectively roadbed box part, part, Bending moment at any section of the segment, ; ——Respectively roadbed box part, part, The maximum bending moment of the segment, ; ——Separate roadbed boxes part, part, Shear force at any section of the segment, ; ——Respectively roadbed box part, part, The maximum shear force of the segment, ; - the connecting shear force of the transverse concave-convex grooves between one end of the middle roadbed box (7) and the adjacent roadbed box, ; ——the allowable bending moment of the roadbed box (7), ; —— allowable shear force of the roadbed box (7), .

2. The construction access road structure on the tidal flat according to claim 1 is characterized in that The roadbed box (7) is a rectangular steel box body welded by a top plate (73), a longitudinal beam (71), a cross beam (72), and a bottom plate (74). Each section is 5 m long and 4 m wide, and 20 cm to 30 cm thick. The longitudinal beam (71) and the cross beam (72) are both I-beams. The top plate (73) and the bottom plate (74) are both steel plates with a thickness of 10 mm to 15 mm. A V-shaped anti-slip strip is welded on the surface of the top plate (73). The overall size and component sizes of the roadbed box (7) are determined according to the width of the construction access road, the load to be borne, and the bearing capacity of the soft soil foundation.

3. The construction access road structure on the tidal flat according to claim 1 is characterized in that Holes are reserved at the four corners of the roadbed box (7), and after paving is completed, latches (75) are driven in as positioning components.

4. The construction access road structure on the tidal flat according to claim 1 is characterized in that The two end heads of each section of the roadbed box (7) are laterally provided with a plurality of convex grooves (76) and a plurality of concave grooves (77). When splicing, the convex grooves (76) and concave grooves (77) corresponding to two adjacent sections of the roadbed box (7) are butted and engaged with each other and then fixed with bolts.

5. The construction access road structure on the tidal flat according to claim 1 is characterized in that The solidified soil (2) utilizes a series of physical and chemical reactions between a solidifying agent and soft soil to harden the soft soil into foundation soil having integrity, water stability and a certain strength. The 7d unconfined compressive strength of the solidified soil (2) is not less than 3MPa.

6. The construction access road structure on the tidal flat according to claim 1 is characterized in that The emulsified asphalt seal layer (3) is a seal layer in which the non-stick emulsified asphalt is sprayed on the top surface of the solidified soil.

7. The construction access road structure on the tidal flat according to claim 1 is characterized in that The crushed stone layer (4) is the main load-bearing structure of the simple roadbed of the construction access road, and is composed of graded crushed stone with a crushed stone particle size of less than 4 cm, a mud content of less than 3%, a thickness of 50 cm to 100 cm, and a compaction degree of not less than 80%; the sand cushion layer (5) is medium-coarse sand, with a mud content of less than 3% and a thickness of 3 cm to 5 cm.

8. The construction access road structure on the tidal flat according to claim 1 is characterized in that The geogrid (6) is a steel-plastic geogrid.

9. A method for constructing a temporary road structure on a tidal flat mud zone according to any one of claims 1 to 8, characterized in that The construction method comprises the following steps: Step 1: Draft a construction access road structure plan on the mudflat area ① According to the construction load borne by the construction access road, geological drilling data and design drawings, the selection of the roadbed box (7) and the thickness and technical indicators of the geogrid (6), sand cushion layer (5), crushed stone layer (4), emulsified asphalt seal layer (3) and solidified soil (2) are determined; ② Calculate the maximum empty length 2a of the bottom of the roadbed box (7) and the corresponding deformation and internal force by using Formulas 1 to 3; Step 2: Solidified soil construction ①Remove impurities from the surface of the treatment area; ②Backfill and level the soft soil according to the designed solidified soil top elevation, and conduct on-site trial mixing before construction. If the mixing head itself is difficult to mix the sinking soil layer, first excavate the soil layer as a whole or partially, and then carry out solidification construction after excavation and rough leveling; ③ Divide the construction area into blocks and divide them into treatment areas with a size of 5m×5m or 5m×6m; ④ Calculate the amount of curing agent according to the soft soil engineering volume of the treatment section, use the curing agent automatic quantitative feeding system to set the curing agent spraying rate, and install the curing agent addition control system in the background feeding system to control the amount of curing agent added in real time, accurately measure, reduce material waste, and record and save the curing agent dosage process in real time to form a report; ⑤ The mixing equipment is directly inserted to mix the in-situ soil; ⑥ The mixing equipment runs forward and gradually stirs and sprays the curing agent until it reaches the bottom of the curing design; ⑦ The mixing equipment runs in reverse, slowly lifts and stirs and sprays the curing agent. The stirring lifting or lowering rate is controlled at 10s / m~20s / m, and the curing agent spraying rate is controlled at 80kg / min~150kg / min. The specific rate is adjusted accordingly according to the actual operation conditions on site to ensure uniform spraying and stirring during the construction process; ⑧After the solidification construction is completed, the construction area is leveled and the surface is compacted to ensure the integrity of the board and the compaction of the surface soil. The solidified soil is cured for more than 7 days and natural curing is adopted. In case of rainy days, plastic film is laid on the surface of the solidification site, and the drainage of the site is strengthened to reduce the impact of rainwater; Step 3: Construction of emulsified asphalt seal layer, crushed stone layer, sand cushion layer and geogrid ① Remove loose soil and debris on the solidified soil (2) base surface, lay out the center line and edge line of the leveling layer, and set up indicator stakes at the edges of the shoulders on both sides for measurement and layout. The elevation is measured using a level; ② Solidified soil (2) Spray the top surface with a non-stick emulsified asphalt seal. The amount of non-stick emulsified asphalt to be spread is converted into pure asphalt at a rate of 0.35kg / m2 to 0.45kg / m2. The seal should be sprayed evenly. ③ Spread the crushed stone evenly on the non-stick wheel emulsified asphalt seal layer of the predetermined width, with each layer of 20cm to 30cm, and compact it layer by layer with a light roller; ④ The sand cushion layer (5) is spread in two times, with the first layer being 1 cm to 2 cm. The geogrid is laid on the first sand cushion layer and flattened. The edges and corners are fixed with soil nails. The geogrid joints overlap, with an overlap width of 50 cm to 100 cm. ⑤ Spread a second layer of sand cushion with a thickness of 1 cm to 2 cm on the geogrid (6) and use a light roller to level it; Step 4: Hoisting the roadbed box ① Use a crane to lay the first section of the roadbed box (7) that has passed the inspection longitudinally along the construction access road, drive steel pins into the reserved holes at the four corners of the roadbed box, and fasten the top of the pins to the top plate of the roadbed box with fasteners, requiring accurate positioning; ② Use a crane to hoist the second section of the roadbed box, and connect the plurality of convex grooves (76) at one end of the second section of the roadbed box with the plurality of concave grooves (77) corresponding to one end of the laid first section of the roadbed box, and then fix them with bolts; ③ Splice all longitudinal roadbed boxes in the above order. If it is a double-lane construction access road, lay the roadbed boxes on the other lane in the same order; ④ Set up horizontal displacement and settlement observation points at appropriate locations on the completed roadbed box (7), conduct the first observation and record; ⑤ Use geological radar to detect the contact between the completed roadbed box and the sand cushion layer as comparative data for the use stage; Step 5: Use and maintain ① After the construction of the roadbed box (7) construction access road is completed, the horizontal displacement, vertical settlement and bottom emptying of the roadbed box are regularly detected by total station and geological radar, so as to understand the dynamics of the roadbed box construction access road and determine whether there is any bottom emptying of the roadbed box. If the roadbed box sways or jumps, it should be detected in time by total station and geological radar; ② If the extent of the roadbed box being emptied reaches a critical value, the roadbed box will be dismantled, repaired, and then the roadbed box will be laid again and put back into use.

Images