An assembled road system suitable for mountainous areas and a design parameter calculation method

Abstract

The present invention discloses an assembled road system suitable for mountain construction and a design parameter calculation method, which relates to the field of assembled building technology, including a Z-shaped structure, backfill, prefabricated road slabs, a surface paving structure and a mountain slope; wherein: a platform is excavated on the mountain slope, and the mountain slope at the upper position of the platform is excavated into a step shape; the Z-shaped structure is laid on the platform excavated on the mountain slope, and the upper end of the Z-shaped structure extends to a side away from the mountain slope; a backfill cavity will be formed between the Z-shaped structure and the mountain slope, and the backfill is filled and arranged in the backfill cavity; the prefabricated road slabs are laid on the top of the backfill; and the surface paving structure is laid on the upper surface of the prefabricated road slabs and the Z-shaped structure. All concrete components in the present invention are prefabricated in the factory and can be transported to the site for assembly, thereby reducing the ecological damage problem of mountain road construction. At the same time, the calculation method provided can accurately calculate the main parameters of the structural design.

Description

Technical Field

[0001] The present invention relates to the technical field of prefabricated buildings, and in particular to a prefabricated road system suitable for construction in mountainous areas and a method for calculating design parameters. Background Art

[0002] The construction of high-grade roads in mountainous areas generally occupies more mountain forests and cultivated land, involves large-scale deforestation, high filling and deep digging, and changes in river courses, which affect the landforms, vegetation, biological communities, the number of animal and plant populations, and animal migration that have been formed over thousands of years. From a macroscopic perspective, it will cause the natural landscape to lose its original state; from a microscopic perspective, it will destroy the functional structure of the ecosystem, causing the internal self-regulation function to be disturbed, resulting in a loss of balance. Therefore, when building roads, it is necessary to minimize the excavation of the original mountain.

[0003] Mountain roads can generally be divided into three categories: cut roadbed, fill roadbed, and half-cut and half-fill roadbed. When the outer side slope is relatively gentle and the fill height is relatively low, fill embankment is usually used to make up for the lack of road width. When the outer side slope is steep, gravity retaining walls, pile-board walls, etc. are usually used, but they use more materials and are difficult to construct, and pile foundations or anchor cables are required; at the same time, the road width cannot be effectively expanded and natural resources cannot be fully utilized. Summary of the invention

[0004] The purpose of the present invention is to provide an assembled road system suitable for construction in mountainous areas and a design parameter calculation method, which solves the problems of road construction and design in mountainous areas.

[0005] The present invention solves the above technical problems through the following technical solutions, which include a Z-shaped structure, backfill soil, a prefabricated road slab, a surface paving structure and a mountain slope; wherein:

[0006] A platform is excavated on the mountain slope, and the mountain slope above the platform is excavated into a step shape;

[0007] The Z-shaped structure is laid on a platform excavated on the mountain slope, and the upper end of the Z-shaped structure extends to a side away from the mountain slope;

[0008] A soil filling cavity will be formed between the Z-shaped structure and the mountain slope, and the backfill soil is filled in the soil filling cavity;

[0009] The prefabricated road slab is laid on top of the backfill soil;

[0010] The surface paving structure is laid on the upper surface of the prefabricated road slab and the Z-shaped structure.

[0011] Preferably, the Z-shaped structure is prefabricated in a factory and comprises a top plate, a web plate and a bottom plate; wherein:

[0012] The upper and lower ends of the web are fixedly connected to the top plate and the bottom plate respectively, the web is arranged obliquely, and the top plate and the bottom plate are staggered laterally to achieve the expansion of the road width.

[0013] Preferably, the top plate is made of lightweight high-strength concrete with a bulk density of less than 19kN / m 3 , grade not less than C40; the web and bottom plates are both made of ordinary concrete, with a grade not less than C40.

[0014] Preferably, a longitudinal connecting pipe is reserved inside the web, and a prestressed steel rod is installed in the connecting pipe; a bottom plate hole is provided on the bottom plate, and a shear key is provided above the tail of the bottom plate.

[0015] Preferably, a pedestal is provided at the inner end of the top plate, a prefabricated bolster is laid on the inner side of the top of the backfill soil, the prefabricated road slab is erected on the pedestal and the prefabricated bolster, and a graded crushed stone layer is filled between the prefabricated road slab and the backfill soil; the surface paving structure includes a waterproof layer and an asphalt concrete layer located on the upper side of the waterproof layer.

[0016] The present invention also proposes a design parameter calculation method for a prefabricated road system suitable for construction in mountainous areas as described above, wherein the length L of the top plate is 1 / 4 to 1 / 2 of the total width W of the road section; the length dimension b of the bottom plate is determined according to the prefabrication, transportation, and hoisting conditions, and the width dimension a of the bottom plate is:

[0017]

[0018] Where, N is the vertical force borne by the bottom surface of the base plate, including dead load and live load; M is the bending moment borne by the bottom surface of the base plate relative to the centroid of the base plate, including dead load and live load; b is the longitudinal dimension of the base plate along the road; σ c Allowable earth pressure stress in foundation;

[0019] Preferably, the vertical inclination angle α of the web is preliminarily formulated as follows:

[0020]

[0021] Among them, L is the length of the top plate, K is the total width of the mountain excavation, W is the total width of the road section, β is the inclination angle of the mountain slope excavation step, and a is the width of the bottom plate.

[0022] Preferably, the thickness c of the web is determined according to the following steps:

[0023] Step 1: Considering the fill load and vehicle load, obtain the soil side pressure σ1 at the top of the web and the soil side pressure σ2 at the bottom of the web;

[0024] Step 2: Calculate the web bending moment caused by the soil side pressure:

[0025] Step 3: Load the vehicle on the top plate according to the most unfavorable eccentric load, and consider the top plate dead load to obtain the web bending moment M caused t ;

[0026] Step 4: Design the allowable stress f of the steel bar according to the design objectives s , the area of ​​tensile reinforcement is A s , that is, calculate the thickness c of the web according to the following formula:

[0027]

[0028] Where: h is the calculated height of the web, σ1 is the soil pressure on the top of the web, σ2 is the soil pressure on the bottom of the web, M t is the bending moment caused by the roof and the vehicle load on it, A s is the tensile reinforcement area in the web, f s is the set allowable stress of the reinforcement.

[0029] The present invention also provides a method for constructing the above-mentioned assembled road system suitable for construction in mountainous areas, comprising the following steps:

[0030] Step 1: Make Z-shaped structure, prefabricated cushion beam and prefabricated road slab in the prefabrication factory; and dig out the platform on the mountain slope;

[0031] Step 2: Use a crane to hoist and install multiple sections of Z-shaped structures onto the platform, and connect them one by one to form a fill cavity;

[0032] Step 3: Backfill the soil excavated from the mountain slope into the inner cavity of the backfill, and lay a layer of graded crushed stone on top of the backfill;

[0033] Step 4: Lay the prefabricated cushion beam on the backfill soil, and lay the prefabricated road slab to the upper side of the Z-shaped structure and the prefabricated cushion beam, and the upper surface of the prefabricated road slab and the top slab are located in the same plane;

[0034] Step 5: Lay the surface paving structure on the upper surface of the prefabricated road slab and the top slab.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. All concrete components in the present invention are prefabricated in the factory and can be transported to the site for assembly without the need to set up pile foundations or anchor rods, thereby speeding up the construction progress and improving efficiency.

[0037] 2. Through the setting of the Z-shaped structure, the top plate of the Z-shaped structure can be extended outward to expand the width of the road, realizing resource saving; and after the backfill cavity formed between the Z-shaped structure and the mountain slope is backfilled with soil, pressure can be applied to the bottom plate of the Z-shaped structure to prevent it from overturning, and the fusion of the structure and the soil can be realized, thereby increasing the durability of the road.

[0038] 3. The top plate adopts lightweight high-strength concrete, inclined web and other special structural designs, and its center of gravity is located on one side of the bottom plate, reducing the risk of structural overturning. The Z-shaped structure is connected into a whole through prestressed steel rods, increasing the stability of the entire structure.

[0039] 4. By setting shear bars on the bottom plate, the combination of the Z-shaped structure and the soil is enhanced to reduce the risk of structural slippage.

[0040] 5. The present invention proposes a calculation formula for the main dimensions of the Z-type structure to ensure the safety, reliability and rationality of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0042] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure of the middle Z-type structure;

[0043] Figure 3 It is a structural schematic diagram of the distribution of prestressed steel bars;

[0044] Figure 4 The main structural diagram of the middle Z-shaped structure;

[0045] Figure 5 It is a schematic diagram of structural parameters;

[0046] Figure 6 Schematic diagram of structural parameters.

[0047] The numbers in the figure represent:

[0048] 1-mountain slope, 2-Z-shaped structure, 21-top plate, 22-web plate, 23-bottom plate, 24-guardrail base, 25-pedestal, 26-connecting pipe, 27-bottom plate hole, 28-shear force, 3-backfill, 4-graded gravel layer, 5-prefabricated road slab, 6-prefabricated cushion beam, 7-prefabricated drainage ditch, 8-assembled steel guardrail, 91-asphalt concrete layer, 92-waterproof layer, 10-prestressed steel rod. DETAILED DESCRIPTION

[0049] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0050] Embodiment 1

[0051] This embodiment provides a technical solution: an assembled road structure suitable for construction in mountainous areas, such as Figure 1-5 As shown, it includes a Z-shaped structure 2, which is prefabricated in sections in a factory, with a section length of 3 to 4 meters, and transported to the construction site for installation along the longitudinal direction of the road. A corresponding platform is excavated at the location of the corresponding mountain slope 1 according to the design requirements, and the Z-shaped structure 2 is placed on the platform of the mountain slope 1.

[0052] The overall cross-section of the Z-shaped structure 2 is "Z"-shaped, and it is formed by integral casting. The overall structure of the Z-shaped structure includes a top plate 21, a web 22 and a bottom plate 23, and the upper and lower ends of the web 22 are fixedly connected to the top plate 21 and the bottom plate 23 respectively. The web 22 is arranged at an angle, and its inclination angle α is 10°~20° to reduce the overturning moment of the structure, and the Z-shaped structure 2 forms a self-stabilizing structure, which is convenient for the transportation and lifting of the Z-shaped structure 2.

[0053] According to the road grade, the total width W of the road section is determined to be 12m, and the top plate size L is 1 / 3W, that is, 4m.

[0054] The bottom plate size a is determined by the following formula: the vertical force N borne by the bottom plate is 950 kN, the bending moment M borne by the bottom plate relative to the centroid of the bottom plate is 1400 kn.m, and the allowable compressive stress σ of the foundation soil is c The pressure is 200kPa, and the longitudinal dimension b of the base plate along the road is 3m.

[0055]

[0056] The vertical inclination angle α of the web 22 can be preliminarily determined by the following formula: a=5m, L=4m, W=12m, K=9m, and β=30°. According to calculation, α=19.8°, so α can be 20°.

[0057]

[0058] The thickness c of the web is determined by the following formula: the soil pressure σ1 on the top of the web is 7 kPa, the soil pressure σ2 on the bottom of the web is 56 kPa, the calculated height h of the web is 2.2 m, and the bending moment M generated by the top plate and the vehicle load on it is obtained: t is 210kN.m, and the tensile reinforcement is configured with 30 HRB400 with a diameter of 14mm, so A s Take 4620mm 2 , is the allowable stress f of the steel bar set to reserve a certain safety margin s Take 260MPa. According to calculation, the thickness c of the web should be greater than 0.363m, and can be taken as 0.4m.

[0059]

[0060] The bottom plate 23 is made of ordinary concrete with a grade not less than C40. The bottom plate 23 is provided with bottom plate holes 27 to enhance the friction between the bottom plate 23 and the soil. A shear bar 28 is provided above the tail of the bottom 23 to enhance the bonding between the Z-shaped structure 2 and the backfill soil 3 and increase the deadweight of the bottom plate 23.

[0061] The top plate 21 and the bottom plate 23 are laterally staggered. When the bottom plate 23 of the Z-shaped structure 2 is placed on the platform of the mountain slope 1, the bottom plate 21 extends to the side away from the mountain slope 1 to expand the width of the road, and a guardrail base 24 is installed on this side. The guardrail base 24 has a reserved guardrail installation groove, and an assembled steel guardrail 8 is installed in the guardrail installation groove.

[0062] The top plate 21 is made of lightweight high-strength concrete with a bulk density of less than 19kN / m 3 , grade not less than C40, to reduce the overturning moment of the structure.

[0063] The joints between the top plate 21 and the web plate 22, and between the web plate 22 and the bottom plate 23 are all provided with haunches.

[0064] The web 22 is made of ordinary concrete with a grade of not less than C40, and a connecting pipe 26 is reserved inside the web 22, and the number of the connecting pipes 26 is not less than 4. The longitudinal direction of the Z-shaped structure 2 is connected as a whole by prestressed steel bars 10 passing through the connecting pipes 26, and the prestressed steel bars 10 are staggered.

[0065] A fill cavity will be formed between the web 22 of the Z-shaped structure 2 and the mountain slope 1, and the fill cavity will be filled with backfill soil 3. The weight of the backfill soil 3 will further exert a downward force on the bottom plate 23 of the Z-shaped structure 2, which can further prevent the Z-shaped structure 2 from overturning.

[0066] The backfill soil 3 is made of waste soil excavated from the mountain, and the backfill compaction degree is not less than 96%. The graded crushed stone layer 4 is made of well-graded crushed stone, and the compaction degree is not less than 98%.

[0067] A pedestal 25 is provided at the inner end of the top plate 21 , a prefabricated cushion beam 6 is laid on the inner side of the top of the backfill soil 3 , and a prefabricated road slab 5 is placed on the pedestal 25 and the prefabricated cushion beam 6 , and the segment length along the longitudinal direction of the road is consistent with that of the Z-shaped structure 2 .

[0068] A graded crushed stone layer 4 is filled between the prefabricated road slab 5 and the backfill soil 3, and the upper surface of the prefabricated road slab 5 is located in the same plane as the upper surface of the top plate 21. A prefabricated drainage ditch 7 is arranged on one side of the entire road section close to the mountain slope 1.

[0069] The prefabricated drainage ditch 7 is prefabricated with fiber concrete, the wall thickness of which is no more than 5 cm, and the segment length along the longitudinal direction of the road is consistent with the Z-shaped structure 2.

[0070] The upper surfaces of the prefabricated road slab 5 and the top slab 21 are jointly provided with a surface paving structure, and the surface paving structure includes a waterproof layer 92 and an asphalt concrete layer 91 located on the upper side of the waterproof layer 92 .

[0071] The mountain slope 1 is excavated into steps along the designed section, the first step is in contact with the bottom surface of the bottom plate 23, and the bearing capacity of the first step foundation is not less than 200kpa. The surface in contact with the backfill 3 is excavated into multiple steps, so that the backfill is closely combined with the excavated mountain to better form the entire road structure.

[0072] Embodiment 2

[0073] A method for constructing an assembled road system suitable for construction in mountainous areas as in the first embodiment comprises the following steps:

[0074] Step 1: Make Z-shaped structure, prefabricated cushion beam and prefabricated road slab in the prefabrication factory; and dig out the platform on the mountain slope;

[0075] Step 2: Use a crane to hoist and install multiple sections of Z-shaped structures onto the platform, connect them one by one, and use prestressed steel rods to connect the Z-shaped structures to form a fill cavity;

[0076] Step 3: Backfill the soil excavated from the mountain slope into the inner cavity of the backfill, and lay a layer of graded crushed stone on top of the backfill;

[0077] Step 4: Lay the prefabricated cushion beam on the backfill soil, and lay the prefabricated road slab to the upper side of the Z-shaped structure and the prefabricated cushion beam, and the upper surface of the prefabricated road slab and the top slab are located in the same plane;

[0078] Step 5: Laying the surface paving structure on the upper surface of the prefabricated road slab and the top slab;

[0079] Step 6: Install the prefabricated steel guardrail.

[0080] The above are only preferred embodiments of the present invention, which are only illustrative and not restrictive. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims, but all of them will fall within the scope of protection of the present invention.

Claims

1. An assembled road system suitable for construction in mountainous areas, characterized by: It includes Z-shaped structure, backfill soil, prefabricated road slab, surface pavement structure and mountain slope; among which: A platform is excavated on the mountain slope, and the mountain slope above the platform is excavated into a step shape; The Z-shaped structure is laid on a platform excavated on the mountain slope, and the upper end of the Z-shaped structure extends to a side away from the mountain slope; A soil filling cavity will be formed between the Z-shaped structure and the mountain slope, and the backfill soil is filled in the soil filling cavity; The prefabricated road slab is laid on top of the backfill soil; The surface paving structure is laid on the upper surface of the prefabricated road slab and the Z-shaped structure; The Z-shaped structure is prefabricated in a factory and includes a top plate, a web plate and a bottom plate; wherein: The upper and lower ends of the web are fixedly connected to the top plate and the bottom plate respectively, the web is arranged obliquely, and the top plate and the bottom plate are arranged transversely staggered to achieve the expansion of the road width; The design parameter calculation method for the prefabricated road system suitable for construction in mountainous areas includes: The length L of the top plate is 1 / 4 to 1 / 2 of the total width W of the road section; the length dimension b of the bottom plate is determined according to the prefabrication, transportation and hoisting conditions, and the width dimension a of the bottom plate is calculated as follows: Where, N is the vertical force borne by the bottom surface of the base plate, including dead load and live load; M is the bending moment borne by the bottom surface of the base plate relative to the centroid of the base plate, including dead load and live load; b is the longitudinal dimension of the base plate along the road; σ c Allowable earth compressive stress in foundation.

2. The assembled road system suitable for construction in mountainous areas according to claim 1, characterized in that: The top plate is made of lightweight high-strength concrete with a bulk density of less than 19kN / m 3 , grade not less than C40; the web and bottom plates are both made of ordinary concrete, with a grade not less than C40.

3. The assembled road system suitable for construction in mountainous areas according to claim 1, characterized in that: A longitudinal connecting pipe is reserved inside the web, and a prestressed steel rod is installed in the connecting pipe; a bottom plate hole is arranged on the bottom plate, and a shear force key is arranged above the tail of the bottom plate.

4. The assembled road system suitable for construction in mountainous areas according to claim 1, characterized in that: A pedestal is provided at the inner end of the top plate, a prefabricated cushion beam is laid on the inner side of the top of the backfill soil, the prefabricated road slab is erected on the pedestal and the prefabricated cushion beam, and a graded crushed stone layer is filled between the prefabricated road slab and the backfill soil; the surface paving structure includes a waterproof layer and an asphalt concrete layer located on the upper side of the waterproof layer.

5. The assembled road system suitable for construction in mountainous areas according to claim 1, characterized in that: The vertical inclination angle α of the web is preliminarily formulated as follows: Among them, L is the length of the top plate, K is the total width of the mountain excavation, W is the total width of the road section, β is the inclination angle of the mountain slope excavation step, and a is the width of the bottom plate.

6. The assembled road system suitable for construction in mountainous areas according to claim 1, characterized in that: The thickness c of the web is determined by the following steps: Step 1: Considering the fill load and vehicle load, obtain the soil side pressure σ1 at the top of the web and the soil side pressure σ2 at the bottom of the web; Step 2: Calculate the web bending moment caused by the soil side pressure: Step 3: Load the vehicle on the top plate according to the most unfavorable eccentric load, and consider the top plate dead load to obtain the web bending moment M caused t ; Step 4: Design the allowable stress f of the steel bar according to the design objectives s , the area of ​​tensile reinforcement is A s , that is, calculate the thickness c of the web according to the following formula: Where: h is the calculated height of the web, σ1 is the soil pressure on the top of the web, σ2 is the soil pressure on the bottom of the web, M t is the bending moment caused by the roof and the vehicle load on it, A s is the tensile reinforcement area in the web, f s is the set allowable stress of the reinforcement.

7. A method for constructing an assembled road system suitable for construction in mountainous areas as claimed in claim 6, characterized in that: The following steps are involved: Step 1: Make Z-shaped structure, prefabricated cushion beam and prefabricated road slab in the prefabrication factory; and dig out the platform on the mountain slope; Step 2: Use a crane to hoist and install multiple sections of Z-shaped structures onto the platform, and connect them one by one to form a fill cavity; Step 3: Backfill the soil excavated from the mountain slope into the inner cavity of the backfill, and lay a layer of graded crushed stone on top of the backfill; Step 4: Lay the prefabricated cushion beam on the backfill soil, and lay the prefabricated road slab to the upper side of the Z-shaped structure and the prefabricated cushion beam, and the upper surface of the prefabricated road slab and the top slab are located in the same plane; Step 5: Lay the surface paving structure on the upper surface of the prefabricated road slab and the top slab.

Images