A design method of drainage ditch suitable for road side slope toe

Abstract

The application discloses a design method of a drainage ditch suitable for a road slope toe, relates to the technical field of drainage ditch design, and determines the height and width of the drainage ditch according to actual water flow conditions, and obtains a gravity expression of the drainage ditch according to the size of the drainage ditch. Then, through overall stress analysis of the drainage ditch, the distribution form of the earth pressure of the side wall of the road side of the drainage ditch is deduced. The traditional design method does not consider the difference between the earth pressure on the two sides, and only designs the two side walls symmetrically according to the stress of the side slope, so that the wall thickness of the side wall of the road side of the drainage ditch is large, more materials are used in construction, a larger space is occupied, and resources are wasted. According to the earth pressure distribution of the side wall of the road side, the wall thickness of the side wall is further calculated and reduced, the accuracy of the calculation result for safety evaluation is improved, and the engineering cost can be saved under the premise of safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drainage ditch design, and particularly relates to a drainage ditch design method suitable for road side slope toe. BACKGROUND

[0002] In actual engineering, many rivers are constructed as open channels along the mountain for landscape and flood discharge function, that is, drainage ditches at the toe of road cutting side slope. At present, the thickness of the two side walls of the drainage ditch and the arrangement of the steel bars are designed according to the side with larger stress. The present application discusses the stress analysis of the earth pressure of the side wall of the drainage ditch at the road side, so as to separately design the two side walls of the asymmetrically loaded drainage ditch at the toe of the road side slope. If the stress of the side slope side is taken to design the two side walls symmetrically, the thickness of the side wall of the road side of the drainage ditch may be large, thereby causing waste. SUMMARY

[0003] One of the purposes of the present application is to provide a drainage ditch design method suitable for the toe of the road side slope. The earth pressure distribution form of the side wall of the road side of the drainage ditch is derived through the overall stress analysis of the drainage ditch, so as to further calculate the thickness of the side wall and the distribution of the steel bars according to the earth pressure distribution, improve the accuracy of the calculation results for safety evaluation, and solve the problem that the thickness of the side wall of the road side of the drainage ditch is large in the existing design method.

[0004] The above purposes of the application can be achieved by the following technical scheme.

[0005] A drainage ditch design method suitable for the toe of the road side slope, comprising the steps of:

[0006] obtaining the size parameters of the drainage ditch, and obtaining the gravity of the drainage ditch according to the size parameters of the drainage ditch, wherein one side of the drainage ditch is a road, and the other side of the drainage ditch is a road side slope;

[0007] establishing the pressure distribution of the drainage ditch at the road side slope side according to the Coulomb active earth pressure, and calculating the pressure distribution of the drainage ditch at the road side according to the gravity of the drainage ditch and the pressure distribution of the drainage ditch at the road side slope side, through the force balance state of the drainage ditch;

[0008] determining the thickness of the side wall of the drainage ditch at the road side according to the pressure distribution of the drainage ditch at the road side.

[0009] The drainage ditch design method suitable for the toe of the road side slope as described above further comprises the following steps of obtaining the size parameters of the drainage ditch, and obtaining the gravity of the drainage ditch according to the size parameters of the drainage ditch, specifically comprising:

[0010] According to the actual displacement demand of the project, the height H and width B of the drainage ditch are determined, and the thickness of the drainage ditch bottom plate and the thickness of the two side walls are preset according to engineering experience;

[0011] According to the height H and width B of the drainage ditch, and the preset thickness of the drainage ditch bottom plate and the thickness of the two side walls of the drainage ditch, the volume of the drainage ditch is obtained;

[0012] According to the volume of the drainage ditch and the density of the drainage ditch, the gravity of the drainage ditch is calculated.

[0013] The drainage ditch design method suitable for the toe of the road slope as described above, further, according to the Coulomb active earth pressure, the pressure distribution of the drainage ditch on one side of the road slope is established, according to the gravity of the drainage ditch and the pressure distribution of the drainage ditch on one side of the road slope, the pressure distribution of the drainage ditch on one side of the road is calculated through the force balance state of the drainage ditch, specifically comprising:

[0014] According to the Coulomb active earth pressure, the active earth pressure E of the drainage ditch on one side of the road slope is calculated a and the active earth pressure E a corresponding to the height Z of the resultant force point ay ; according to the active earth pressure E a in the horizontal and vertical directions, the horizontal component of the active earth pressure E ax and the vertical component of the active earth pressure E ay ; the earth pressure resultant force of the drainage ditch on one side of the road is set as E d , the earth pressure resultant force E d corresponding to the height Z dy of the resultant force point; the gravity of the drainage ditch is G;

[0015] Through the force balance state of the drainage ditch, the following formula is obtained:

[0016] E d =E ax -μ(G+E ay )

[0017]

[0018] In the formula, μ is the base friction coefficient,

[0019] The earth pressure resultant force E d of the drainage ditch on one side of the road and the height Z dy corresponding to the resultant force point are calculated by the above formula.

[0020] The design method for the drainage ditch suitable for the road side slope toe further determines the side wall thickness of the drainage ditch on one side of the road according to the pressure distribution of the drainage ditch on one side of the road, and specifically comprises the following steps.

[0021] According to the Rankine earth pressure theory, the active earth pressure E of the drainage ditch on one side of the road is determined da and the passive earth pressure E dp and the distribution form are determined.

[0022] According to the relationship among the resultant force of the earth pressure E d , the active earth pressure E da and the passive earth pressure E dp , and according to the relationship between the height Z of the resultant force action point dy and the height of the resultant force action point of the critical point of the triangular distribution and the trapezoidal distribution, the distribution form of the resultant force of the earth pressure E d is determined.

[0023] According to the distribution form of the resultant force of the earth pressure E d , the side wall thickness of the drainage ditch on one side of the road is determined.

[0024] The design method for the drainage ditch suitable for the road side slope toe further determines the active earth pressure E da and the passive earth pressure E dp of the drainage ditch on one side of the road according to the Rankine earth pressure theory, and specifically comprises the following steps.

[0025] The active earth pressure is distributed in a triangular form, and is calculated according to the following formula:

[0026]

[0027] In the formula, E da is the active earth pressure, γ is the natural specific gravity of the earth body, K a is the dynamic earth pressure coefficient, and Z0 is the critical depth of the active earth pressure.

[0028] The dynamic earth pressure coefficient K a is calculated according to the following formula:

[0029]

[0030] The critical depth of the active earth pressure z0 is calculated according to the following formula:

[0031]

[0032] The passive earth pressure is distributed in a trapezoidal form, and is calculated according to the following formula:

[0033]

[0034] E = K * γ * H dp K = K' * (c / γ) + 1 p K' = K' * (c / γ) + 1

[0035] K' = K' * (c / γ) + 1 p According to the following formula:

[0036]

[0037] The design method for the drainage ditch at the toe of the road slope, further, according to the magnitude relationship between the earth pressure resultant force E d , the active earth pressure E da and the passive earth pressure E dp and the distribution form, the distribution form of the earth pressure resultant force E d is determined, specifically including:

[0038] The active earth pressure E d and the passive earth pressure E da calculated by Rankine earth pressure theory are compared with the earth pressure resultant force E dp , when the active earth pressure E da < earth pressure resultant force E d < passive earth pressure E dp , the distribution form of the earth pressure resultant force E d should be between triangular distribution and trapezoidal distribution.

[0039] The design method for the drainage ditch at the toe of the road slope, further, according to the relationship between the height Z dy of the resultant force point and the height of the resultant force point of the critical point of the triangular distribution and the trapezoidal distribution, the distribution form of the earth pressure resultant force E d is determined, specifically including:

[0040] If the height Z dy of the corresponding resultant force point is less than or equal to the height H / 3 of the resultant force point of the critical point of the triangular distribution and the trapezoidal distribution, the distribution form of the earth pressure resultant force E d on this side is triangular distribution;

[0041] If the height Z dy of the corresponding resultant force point is greater than the height H / 3 of the resultant force point of the critical point of the triangular distribution and the trapezoidal distribution, the distribution form of the earth pressure resultant force E d on this side is trapezoidal distribution.

[0042] Compared with the prior art, the method provided by the application meets the safe and economic design principle, is more in line with the actual asymmetric loading condition of a road side slope, and is applicable to the construction of a drainage channel at the toe of the side slope and other actual projects. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art based on the drawings without creative effort should be within the protection scope of the present application.

[0044] Figure 1 A drainage channel cross-sectional view of the embodiment of the present application is shown in the figure.

[0045] Figure 2 A side slope side wall active earth pressure distribution diagram of the embodiment of the present application is shown in the figure.

[0046] Figure 3 A drainage channel overall force balance diagram for deriving the side wall earth pressure force and its action point of the embodiment of the present application is shown in the figure.

[0047] Figure 4 A side wall earth pressure distribution form diagram derived according to the side wall earth pressure force and its action point of the embodiment of the present application is shown in the figure.

[0048] Figure 5 A method flow chart of the drainage channel design method suitable for the toe of a road side slope of the embodiment of the present application is shown in the figure.

[0049] In the figure: 1. drainage channel, 2. side slope side wall of the drainage channel, 3. road side side wall of the drainage channel, 4. bottom plate of the drainage channel, 5. road side slope. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should be within the protection scope of the present application.

[0051] Embodiment:

[0052] It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units need not be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 5 A flowchart of the design method of the drainage ditch suitable for the road slope toe in the embodiments of the present application is shown. Figure 5 As shown in the figure, the design method of the drainage ditch suitable for the road slope toe provided by the embodiments of the present application can specifically include the following steps:

[0054] Step 1: Obtain the size parameters of the drainage ditch, and obtain the gravity of the drainage ditch according to the size parameters of the drainage ditch and the density of the drainage ditch, wherein one side of the drainage ditch is a road, and the other side of the drainage ditch is a road slope.

[0055] Specifically, it includes the steps of: determining the height H and the width B of the drainage ditch according to the actual drainage demand of the project, and presetting the thickness of the bottom plate and the thickness of the two side walls of the drainage ditch according to engineering experience; obtaining the volume of the drainage ditch according to the height H and the width B of the drainage ditch, and the preset thickness of the bottom plate and the two side walls of the drainage ditch; and calculating the gravity of the drainage ditch according to the volume of the drainage ditch and the density of the drainage ditch.

[0056] Figure 1 A drainage ditch cross-sectional view in the embodiments of the present application is shown. Figure 2 As shown in the figure, the left side of the drainage ditch is a road, and the right side is a road slope, wherein the left side wall of the drainage ditch is a road side wall, and its thickness is b1; the right side wall of the drainage ditch is a slope side wall, and its thickness is b3; the net width of the drainage ditch is b2, and the width B of the drainage ditch can be determined by b1, b2 and b3; the net height of the drainage ditch is h1, and the thickness of the bottom of the drainage ditch is the thickness of the bottom plate, which is h2, and the height H of the drainage ditch can be determined by h1 and h2.

[0057] Step 2: Establish the pressure distribution of the drainage ditch on one side of the road slope according to the Coulomb active earth pressure, and calculate the pressure distribution of the drainage ditch on one side of the road according to the gravity of the drainage ditch and the pressure distribution of the drainage ditch on one side of the road slope, and obtain the pressure distribution of the drainage ditch on one side of the road by the force balance state of the drainage ditch.

[0058] Specifically, it includes the steps of: calculating the active earth pressure E a of the drainage ditch on one side of the road slope according to the Coulomb active earth pressure, and the height Z of the corresponding resultant force point of the active earth pressure E a of the drainage ditch on one side of the road slope.ay According to the active earth pressure E a The horizontal and vertical components of the force are used to obtain the horizontal component of the active earth pressure, E. ax And the vertical component of active earth pressure E ay Let the resultant earth pressure of the drainage ditch on one side of the road be E. d The resultant earth pressure is E d The height of the corresponding point of application of the resultant force is Z. dy The weight of the drainage ditch is G;

[0059] The drainage ditch is in a state of force equilibrium, resulting in the following formula:

[0060] E d =E ax -μ(G+E ay )

[0061]

[0062] In the formula, μ is the substrate friction coefficient.

[0063] The resultant earth pressure E of the drainage ditch on one side of the road is calculated using the above formula. d And the height Z of the corresponding resultant force application point dy .

[0064] Step 3: Determine the thickness of the sidewall of the drainage ditch on one side of the road based on the pressure distribution of the drainage ditch on one side of the road.

[0065] The specific implementation includes the following steps: determining the active earth pressure E of the drainage ditch on one side of the road based on Rankine's earth pressure theory. da and passive earth pressure E dp Distribution pattern: Based on the resultant earth pressure E d Active earth pressure E da and passive earth pressure E dp The relationship between them, and, according to the resultant earth pressure E d The height Z of the point of application of the resultant force ay and active earth pressure E da The height of the point of application of the resultant force and the passive earth pressure E dp The relationship between the heights of the points of application of the resultant force and the earth pressure resultant force E is used to determine the earth pressure resultant force E. d The distribution pattern; based on the resultant earth pressure E d The distribution pattern determines the thickness of the sidewall of the drainage ditch on one side of the road.

[0066] The active earth pressure E of the drainage ditch on one side of the road is determined based on Rankine's earth pressure theory. da and passive earth pressure E dp and distribution patterns, specifically including:

[0067] The active earth pressure is distributed in a triangular shape and is calculated according to the following formula:

[0068]

[0069] In the formula, E da is the active earth pressure, γ is the natural density of the soil, K a is the active earth pressure coefficient, and Z0 is the critical depth of the active earth pressure.

[0070] The active earth pressure coefficient K a is calculated according to the following formula:

[0071]

[0072] The critical depth of the active earth pressure Z0 is calculated according to the following formula:

[0073]

[0074] The passive earth pressure is distributed in a trapezoidal shape and is calculated according to the following formula:

[0075]

[0076] In the formula, E dp is the passive earth pressure, γ is the natural density of the soil, K p is the passive earth pressure coefficient, and c is the cohesion.

[0077] The passive earth pressure coefficient K p is calculated according to the following formula:

[0078]

[0079] In which, according to the size relationship between the earth pressure resultant force E d , the active earth pressure E da and the passive earth pressure E dp and the distribution form, the distribution form of the earth pressure resultant force E d is determined, specifically including:

[0080] The earth pressure resultant force E d is compared with the active earth pressure E da and the passive earth pressure E dp calculated according to the Rankine earth pressure theory, when the active earth pressure E da < the earth pressure resultant force E d < the passive earth pressure E dp , the distribution form of the earth pressure resultant force E d should be between the triangular distribution and the trapezoidal distribution.

[0081] Among them, based on the height Z of the point of application of the resultant force dy The relationship between the height of the resultant force point of the triangular and trapezoidal distributions and the critical points of the earth pressure distributions is used to determine the resultant earth pressure E. d Distribution pattern:

[0082] If the height of the corresponding resultant force application point Z dy When the resultant force on that side is less than or equal to the height H / 3 of the point of application of the resultant force at the critical point of the triangular or trapezoidal distribution, the resultant earth pressure E... d The distribution pattern is triangular;

[0083] If the height of the corresponding resultant force application point Z dy When the height H / 3 of the point of application of the resultant force is greater than the critical point of the triangular or trapezoidal distribution, the resultant earth pressure E on that side is... d The distribution pattern is trapezoidal.

[0084] As a preferred embodiment, the drainage ditch design method for the toe of a roadside slope provided by this invention may specifically include the following steps:

[0085] Step S1: Determine the height and width of the drainage ditch based on the actual drainage volume required by the project. Based on the principles of this invention, the thickness of the drainage ditch's bottom slab and the thickness of its side walls can be preset according to engineering experience.

[0086] Step S2: Based on the height and width of the drainage ditch, as well as the preset thickness of the bottom plate and the side wall, the volume of the drainage ditch can be obtained. The weight of the drainage ditch can then be obtained from the volume and the density of the drainage ditch.

[0087] Step S3: Calculate the lateral earth pressure on the sidewall of the slope. Using Coulomb's active earth pressure calculation, obtain the active earth pressure E on the sidewall of the drainage ditch slope. a and the corresponding point of application of the resultant force Z ay The lateral earth pressure relative to the lateral earth bending moment of the drainage ditch is calculated. Lateral earth pressure refers to the force exerted by the soil on the structure. Lateral earth pressure can generate a bending moment on the drainage ditch. The lateral earth pressure and the lateral earth bending moment generated by the lateral earth pressure are calculated based on the size of the drainage ditch and the properties of the soil itself.

[0088] Step S4: Based on the overall analysis of the drainage ditch, it is found to be in a state of force equilibrium. Using the drainage ditch dimensions and gravity determined in Step S2, and the lateral earth pressure and bending moment of the slope sidewalls determined in Step S3, an equilibrium equation is established. From this equation, the resultant earth pressure on the drainage ditch sidewalls and its point of application can be obtained. The equilibrium equation is:

[0089] E d =E ax -μ(G+E ay )

[0090]

[0091] In the formula, E d E is the resultant earth pressure on the sidewall of the drainage channel. ax Let μ be the horizontal component of the active earth pressure on the sidewall of the drainage ditch slope, G be the base friction coefficient, and E be the self-weight of the drainage ditch. ay Z is the vertical component of the active earth pressure on the sidewall of the drainage ditch slope; dy B is the height of the point of application of the resultant earth pressure on the side wall of the drainage channel, and Z is the width of the drainage channel. ay The height is the point of application of the resultant earth pressure on the side wall of the drainage ditch slope.

[0092] Step S5: Calculate the distribution and resultant force of active and passive earth pressure on the sidewall of the drainage channel based on Rankine's earth pressure theory.

[0093] The active earth pressure on the sidewall of the drainage channel is distributed in a triangular pattern and is calculated using the following formula:

[0094]

[0095] The active earth pressure coefficient K on the roadside a The following formula is used to calculate:

[0096]

[0097] The critical depth z0 of the active earth pressure on the roadside is calculated according to the following formula:

[0098]

[0099] The height Z of the resultant point of action of the active earth pressure on the roadside day The following formula is used to calculate:

[0100]

[0101] The passive earth pressure on the sidewall of the drainage channel is distributed in a trapezoidal shape and can be calculated using the following formula:

[0102]

[0103] The passive earth pressure coefficient K on the roadside p The following formula is used to calculate:

[0104]

[0105] The height Z of the point of application of the resultant passive earth pressure on the roadside dpy The following formula is used to calculate:

[0106]

[0107] Step S6: the actual earth pressure E d active earth pressure E da and passive earth pressure E dp It is found that the actual earth pressure is between the active earth pressure and the passive earth pressure, i.e. the active earth pressure E da <the earth pressure of the side wall of the drainage ditch on the road side E d <the passive earth pressure of the road side E dp ; at the same time, the height Z of the action point of the resultant force of the actual earth pressure obtained in step S4 dy and the height Z of the action point of the resultant force of the active earth pressure obtained in step S5 day , the height Z of the action point of the resultant force of the passive earth pressure obtained in step S6 dpy are compared, and the height Z of the action point of the resultant force of the active earth pressure of the road side day <the height Z of the action point of the resultant force of the earth pressure of the side wall of the drainage ditch on the road side dy <the height Z of the action point of the resultant force of the passive earth pressure of the road side dpy , see Figure 4 Therefore, the earth pressure distribution form of the side wall of the drainage ditch on the road side should be between the triangular distribution and the trapezoidal distribution.

[0108] Step S7: in order to further determine the earth pressure distribution form of the side wall of the drainage ditch on the road side, the earth pressure distribution form of the side wall of the drainage ditch on the road side is deduced according to the relationship between the action point of the resultant force of the actual earth pressure and the action point of the resultant force of the critical point of the triangular and trapezoidal distribution;

[0109] If the action point Z of the resultant force of the earth pressure of the side wall of the drainage ditch on the road side dy is less than or equal to the action point H / 3 of the resultant force of the critical point of the triangular and trapezoidal distribution, the earth pressure distribution of the side is the triangular distribution;

[0110] If the action point Z of the resultant force of the earth pressure of the side wall of the drainage ditch on the road side dy is greater than the action point H / 3 of the resultant force of the critical point of the triangular and trapezoidal distribution, the earth pressure distribution of the side is the trapezoidal distribution;

[0111] Step S8: according to the earth pressure distribution form, the side wall of the drainage ditch on the road side is designed, and under the premise that the cross-section bearing capacity and the crack meet the requirements, the wall thickness b1 is further reduced.

[0112] Please refer to Figure 1 , the height of the slope is 8m, the slope ratio is 1:1.5, the width of the slope falling platform is 1m. The soil layer is homogeneous soil, the cohesion c is 10kPa, the internal friction angle φ is 20°, the natural density of the soil body γ is 19kN / m3, the friction coefficient of the base μ is 0.25, and the weight of the water in the culvert is ignored according to the adverse factor.

[0113] Step S1: According to the drainage requirement, the net height h1 of the drainage ditch is 4 m, the bottom plate thickness h2 is 0.5 m, the total height H is 4.5 m; the road side side wall thickness b1 is 0.3 m, the drainage ditch net width b2 is 3 m, the side slope side wall thickness b3 is 0.4 m, and the total width B is 3.7 m.

[0114] Step S2: The drainage ditch adopts a reinforced concrete structure, and the unit weight is 26 kN / m3. According to the size of the drainage ditch, the volume per meter is 4.65 m 3 , and the self weight G of the drainage ditch is 120.9 kN / m.

[0115] Step S3: The side soil pressure of the side slope side wall is calculated according to the Coulomb active earth pressure, and the specific earth pressure distribution is shown in Figure 2 ;

[0116] Active earth pressure E a = 156.2 kN / m;

[0117] Horizontal component of active earth pressure E ax = 149 kN / m;

[0118] Vertical component of active earth pressure E ay = 47 kN / m;

[0119] Height of action point Z ay = 1.483 (m).

[0120] Step S4: Referring to Figure 3 , the horizontal component of the active earth pressure of the side slope E ax = 149 kN / m, the base friction coefficient μ = 0.25, the self weight of the drainage ditch G = 120.9 kN / m, and the vertical component of the active earth pressure E ay = 47 kN / m are substituted into the following horizontal force balance equation:

[0121] E d = E ax - μ (G + E ay )

[0122] The resultant force of the road side soil pressure E d = 107.025 kN / m

[0123] Referring to Figure 3 , the above data and the total width B of the drainage ditch = 3.7 are substituted into the following bending moment balance equation:

[0124]

[0125] The action point Z of the resultant force of the road side soil pressure E dy = 1.25 m

[0126] Step S5: The active earth pressure of the drainage ditch road side side wall is distributed in a triangular shape, see Figure 4 (a)

[0127] wherein the road side active earth pressure coefficient

[0128] The critical depth of the road side active earth pressure

[0129] The road side active earth pressure

[0130] The passive earth pressure of the drainage ditch road side side wall is distributed in a trapezoidal shape, see Figure 4 (c)

[0131] wherein the road side passive earth pressure coefficient

[0132] The road side passive earth pressure

[0133]

[0134] Step S6: The road side active earth pressure E da = 41.83 kN / m < the actual road side earth pressure E d = 107.025 kN / m < the passive road side earth pressure E dp = 420.93 kN / m, so the earth pressure distribution form of the drainage ditch road side side wall should be between the triangular distribution and the trapezoidal distribution.

[0135] Step S7: In order to further determine the earth pressure distribution form of the road side side wall, according to the relationship between the actual earth pressure force point of the side and the force point of the triangular and trapezoidal distribution critical point, the distribution form of the actual earth pressure of the drainage ditch road side side wall is derived;

[0136] The earth pressure force point Z of the drainage ditch road side side wall dy = 1.25 m is less than the force point H / 3 = 1.5 m of the triangular and trapezoidal distribution critical point, so the earth pressure distribution of the side is still triangular, see Figure 4 (b). At this time, the height of the earth pressure distribution is 1.25 x 3 = 3.75 m.

[0137] Step S8: The bending moment combination design value Mbd of the side slope side wall is 146.5 kN·m, and the bending moment combination design value Mdd of the road side side wall is 74.7 N·m. According to the "Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts" (JTG3362-2018), in order to meet the requirements of cross-section reinforcement bearing capacity and crack, the wall thickness of the side slope side is 400 mm, and the wall thickness of the road side is 300 mm, and Φ25@100 mm reinforcement is configured.

[0138] According to the distribution form of the actual earth pressure, the side wall of the drainage ditch road side is designed, and under the premise that the cross-section bearing capacity review and the crack meet the requirements, the wall thickness is optimized from the symmetrical 400mm of both sides to the wall thickness of 400mm of the slope side and the wall thickness of 300mm of the road side.

[0139] The calculation process table is as follows

[0140]

[0141]

[0142] From the above results, it can be concluded that the drainage ditch wall thickness designed by the analysis and calculation method proposed in the application is more economical.

[0143] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

Claims

1. A method for designing a drainage ditch suitable for use at a toe of a road slope, characterized by, The method comprises the steps of: obtaining size parameters of the drainage ditch, and obtaining gravity of the drainage ditch according to the size parameters of the drainage ditch, wherein one side of the drainage ditch is a road, and the other side of the drainage ditch is a road slope; establishing pressure distribution of the drainage ditch on the road slope side according to Coulomb active earth pressure, and obtaining pressure distribution of the drainage ditch on the road side by calculating the drainage ditch in a force balance state according to the gravity of the drainage ditch and the pressure distribution of the drainage ditch on the road slope side; The thickness of the sidewall of the drainage ditch on the road side is determined based on the pressure distribution along the ditch, wherein the active earth pressure on the road side of the drainage ditch is determined according to Rankine's earth pressure theory. and passive earth pressure Distribution pattern: Based on the resultant force of earth pressure Active earth pressure and passive earth pressure The relationship between them, and based on the height of the point of application of the resultant force. The relationship between the height of the resultant force application point of the critical points of the triangular and trapezoidal distributions is used to determine the resultant earth pressure. The distribution pattern; based on the resultant earth pressure The distribution pattern determines the thickness of the sidewall of the drainage ditch on one side of the road.

2. The method for designing a drainage ditch suitable for a road slope toe according to claim 1, wherein, obtaining size parameters of the drainage ditch, and obtaining gravity of the drainage ditch according to the size parameters of the drainage ditch, specifically comprising: determining height H and width B of the drainage ditch according to actual drainage demand of a project, and presetting thickness of a bottom plate and thickness of two side walls of the drainage ditch according to engineering experience; obtaining volume of the drainage ditch according to the height H and the width B of the drainage ditch, and the preset thickness of the bottom plate and the thickness of the two side walls of the drainage ditch; obtaining gravity of the drainage ditch according to the volume of the drainage ditch and density of the drainage ditch.

3. The method for designing a drainage ditch suitable for a road slope toe according to claim 2, wherein establishing pressure distribution of the drainage ditch on the road slope side according to Coulomb active earth pressure, and obtaining pressure distribution of the drainage ditch on the road side by calculating the drainage ditch in a force balance state according to the gravity of the drainage ditch and the pressure distribution of the drainage ditch on the road slope side, specifically comprising: The active earth pressure on the side of the road slope of the drainage ditch is calculated according to the Coulomb active earth pressure and the active earth pressure corresponding to the height of the action point of the resultant force ; according to the active earth pressure , the horizontal and vertical components of the active earth pressure are obtained, that is, the horizontal component of the active earth pressure and the vertical component of the active earth pressure ; the earth pressure resultant force on the side of the road of the drainage ditch is set as , the earth pressure resultant force is , and the height of the action point of the corresponding resultant force is ; the gravity of the drainage ditch is G; obtaining the following formula by the drainage ditch in a force balance state: In the formula, is the coefficient of friction of the substrate, The resultant force of the earth pressure on one side of the road is calculated by the above formula and the height of the corresponding resultant force point .

4. The method for designing a drainage ditch suitable for a road slope toe according to claim 1, wherein determining the active earth pressure on one side of the road according to Rankine's earth pressure theory and passive earth pressure and the distribution form, in particular comprising: the active earth pressure is distributed in a triangular shape, and is obtained according to the following formula: ； wherein is the active earth pressure, γ is the natural density of the soil, is the dynamic earth pressure coefficient, is the critical depth of the active earth pressure; Active earth pressure coefficient The active earth pressure coefficient is calculated according to the following formula: ； Critical depth of active earth pressure The critical depth is calculated according to the formula: ； the passive earth pressure is distributed in a trapezoidal shape, and is obtained according to the following formula: ； wherein is the passive earth pressure, γ is the natural unit weight of the soil, is the passive earth pressure coefficient, c is the cohesion, Passive earth pressure coefficient The passive earth pressure coefficient is calculated according to the following formula: 。 5. The method for designing a drainage ditch suitable for a road slope toe according to claim 4, wherein According to the resultant force of earth pressure Active earth pressure and passive earth pressure The relationship between them, and based on the height of the point of application of the resultant force. The relationship between the height of the resultant force application point of the critical points of the triangular and trapezoidal distributions is used to determine the resultant earth pressure. The distribution patterns specifically include: The resultant of earth pressure The active earth pressure calculated by Rankine's theory and the passive earth pressure are compared, when the active earth pressure The resultant of earth pressure The passive earth pressure The distribution of the resultant of earth pressure should be between triangular and trapezoidal distribution.

6. The method for designing a drainage ditch suitable for a road slope toe according to claim 5, wherein, The height of the resultant force point according to the height The relationship between the height of the resultant force point of the critical point of the triangular distribution and the trapezoidal distribution determines the distribution form of the earth pressure resultant force , specifically including: If the height of the corresponding resultant force application point When the resultant force on that side is less than or equal to the height H / 3 of the point of application of the resultant force at the critical point of the triangular or trapezoidal distribution, the resultant earth pressure on that side is... The distribution pattern is triangular; If the height of the corresponding resultant force application point When the height H / 3 of the point of application of the resultant force is greater than the critical point of the triangular or trapezoidal distribution, the resultant earth pressure on that side is... The distribution pattern is trapezoidal.

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