Method for controlling settlement of road culvert in soft soil foundation

Abstract

The application provides a soft soil foundation road culvert settlement control method, which comprises the following steps: a calculation step, wherein a target object is subjected to soft foundation treatment, and post-construction settlement of the target object is calculated, the target object comprises a box culvert and a roadbed; a determination step, wherein a transition section is arranged at a joint of the box culvert and the roadbed, a length of the transition section is calculated according to post-construction settlement of the box culvert and post-construction settlement of the roadbed, and settlement parameters of the box culvert and the roadbed are determined. In the application, post-construction settlement of the box culvert and the roadbed is calculated first, then a transition section is arranged at a joint of the box culvert and the roadbed, the length of the transition section is calculated according to post-construction settlement of the box culvert and post-construction settlement of the roadbed, and settlement parameters of the box culvert and the roadbed are determined, construction is carried out according to the settlement parameters of the box culvert and the roadbed, the settlement difference at the joint of the box culvert and the roadbed can be effectively reduced, bumping and cracks caused by uneven settlement at the joint of the box culvert and the roadbed are reduced, the construction quality and safety of the road are improved, and the traffic comfort at the box culvert is ensured.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, and more specifically, to a method for controlling settlement of road culverts on soft soil foundations. Background Technology

[0002] Soft soil foundations are characterized by low shear strength, poor stability, and poor bearing capacity. During construction, soft soil treatment is necessary. Improper treatment can lead to problems such as vehicle bouncing and cracking after traffic begins, and in severe cases, even safety accidents. Current roadbed design specifications stipulate that the allowable post-construction settlement for culverts on expressways and Class I highways should not exceed 200mm, and the allowable post-construction settlement for roadbeds should not exceed 300mm; for other grades of highways, the allowable post-construction settlement for culverts should not exceed 300mm, and the allowable post-construction settlement for roadbeds should not exceed 500mm. Even under the condition of meeting roadbed design specifications, significant uneven settlement differences may exist at the junction of culverts and roadbeds, reducing road construction quality and potentially leading to vehicle bouncing, cracking, and other problems, thus reducing road safety. Summary of the Invention

[0003] In view of this, the present invention proposes a method for controlling the settlement of road culverts on soft soil foundations, aiming to solve the problem that uneven settlement at the junction of culverts and roadbeds in the prior art can easily reduce the quality of road construction.

[0004] This invention proposes a method for controlling the settlement of road culverts on soft soil foundations. The method includes the following steps: a calculation step, in which the target object is subjected to soft soil treatment and the post-construction settlement of the target object is calculated, wherein the target object includes: a box culvert and a roadbed; and a determination step, in which a transition section is set at the junction of the box culvert and the roadbed, the length of the transition section is calculated based on the post-construction settlement of the box culvert and the roadbed, and the settlement parameters of the box culvert and the roadbed are determined.

[0005] Furthermore, in the above-mentioned method for controlling the settlement of road culverts on soft soil foundations, when the box culvert and the roadbed are treated with the same soft soil treatment method, in the calculation step, when calculating the post-construction settlement of the box culvert, the soft soil treatment depth D1 of the box culvert is set; when calculating the post-construction settlement of the roadbed, the soft soil treatment depth D2 of the roadbed is set; in the determination step, a transition section is set at the junction of the box culvert and the roadbed within the range of the soft soil treatment depth, and the soft soil treatment depth D1 of the box culvert is determined as the thickness of the soft soil treatment at the box culvert, and the soft soil treatment depth D2 of the roadbed is determined as the thickness of the soft soil treatment at the roadbed.

[0006] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, when the box culvert and the roadbed are treated with different soft soil treatment methods, in the determination step, a transition section is set at the junction of the box culvert and the roadbed within the overload preloading range, and the preloading height at the box culvert is set as h1, and the preloading height at the roadbed is set as h2, where h1 > h2.

[0007] Furthermore, in the aforementioned method for controlling settlement of road culverts on soft soil foundations, the calculation steps further include: a sub-step for calculating primary consolidation settlement, which calculates the primary consolidation settlement S based on the drainage distance, the average initial effective stress of the soil layer, and the additional effective stress. t The sub-step for calculating secondary consolidation settlement calculates the secondary consolidation settlement S2 based on the soft soil layer thickness, the completion time of primary consolidation, and the secondary consolidation settlement time. The sub-step for calculating post-construction settlement calculates the settlement based on the primary consolidation settlement S2. t Calculation of post-consolidation settlement S2 and secondary consolidation settlement S p .

[0008] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, the calculation sub-step for principal consolidation settlement is based on the formula... Calculate the principal consolidation settlement S t In the formula, Cˊ c The coefficient of compression in a one-dimensional consolidation test is given by H, where H is the drainage distance. σ is the average initial effective stress of the soil layer. c To add effective stress.

[0009] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, the sub-step for calculating secondary consolidation settlement is based on the formula... Calculate the secondary consolidation settlement S2; where Cˊ a Here, H is the subcompression coefficient, H is the thickness of the soft soil layer, and t is the t value. p t is the time for primary consolidation to complete, and t is the time for secondary consolidation to settle.

[0010] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, the post-construction settlement calculation sub-step is based on formula S. p =S t +S2-S cp Calculate the post-construction settlement S p In the formula, S cp For construction period settlement, the construction period settlement S cp The determination is based on the principle of consolidation and seepage in saturated soil and the construction period.

[0011] Furthermore, in the aforementioned method for controlling settlement of road culverts on soft soil foundations, the post-construction settlement calculation sub-step includes the post-construction settlement S of the box culvert. p1 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0012] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, the post-construction settlement calculation sub-step includes the post-construction settlement S of the roadbed. p2 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0013] Furthermore, in the above-mentioned method for controlling settlement of road culverts on soft soil foundations, in the determination step, the uneven settlement difference at the junction of the box culvert and the roadbed is set to be less than or equal to i%, where i is less than or equal to 1; the length of the transition section L ≥ (S p2 -S p1) / i%.

[0014] In this invention, the post-construction settlement of the box culvert and the roadbed is first calculated. Then, a transition section is set at the junction of the box culvert and the roadbed. The length of the transition section is calculated based on the post-construction settlement of the box culvert and the roadbed, and the settlement parameters of the box culvert and the roadbed are determined. Construction is carried out based on the settlement parameters of the box culvert and the roadbed. This can effectively reduce the settlement difference at the junction of the box culvert and the roadbed, reduce vehicle bounce and cracks caused by uneven settlement at the junction of the box culvert and the roadbed, improve the construction quality and safety of the road, and thus ensure the traffic comfort at the box culvert. This solves the problem in the prior art that uneven settlement difference at the junction of the culvert and the roadbed can easily reduce the quality of road construction. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0016] Figure 1 A flowchart of a method for controlling settlement of road culverts on soft soil foundations provided in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of the method for controlling settlement of road culverts on soft soil foundations provided in an embodiment of the present invention. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] See Figure 1 , Figure 1 A flowchart illustrating a method for controlling settlement of road culverts on soft soil foundations, provided in an embodiment of the present invention. As shown in the figure, the method for controlling settlement of road culverts on soft soil foundations includes the following steps:

[0020] Calculation step S1 involves performing soft soil treatment on the target object and calculating the post-construction settlement of the target object, wherein the target object includes: box culvert and roadbed.

[0021] Specifically, when treating soft soil conditions for box culverts and roadbeds, the same or different methods can be used, making both applicable to various methods. Regardless of the method used, the method for calculating post-construction settlement remains the same. Furthermore, the method for calculating the post-construction settlement of box culverts is identical to that for roadbeds; only the input data differs.

[0022] Calculation step S1 further includes:

[0023] In the primary consolidation settlement calculation sub-step S11, the primary consolidation settlement S is calculated based on the drainage distance, the average initial effective stress of the soil layer, and the additional effective stress. t .

[0024] Specifically, the primary consolidation settlement S is calculated using the layered summation method. t Main consolidation settlement S t The calculation method is as follows: according to the formula Calculate the principal consolidation settlement S t In the formula, Cˊ c The coefficient of compression in a one-dimensional consolidation test is given by , and H is the drainage distance. σ is the average initial effective stress of the soil layer. c This is the additional effective stress. Where, σ c This refers to the additional effective stress generated by the externally applied load.

[0025] When calculating the post-construction settlement of a box culvert, the principal consolidation settlement S t The parameters in the calculation formula are the design parameters of the box culvert; when calculating the post-construction settlement of the roadbed, the principal consolidation settlement S t The parameters in the calculation formula are the design parameters of the roadbed.

[0026] Sub-step S12 for calculating secondary consolidation settlement: Calculate secondary consolidation settlement S2 based on the thickness of the soft soil layer, the completion time of primary consolidation, and the settlement time of secondary consolidation.

[0027] Specifically, according to the formula Calculate the secondary consolidation settlement S2; where Cˊ a Here, H is the subcompression coefficient, H is the thickness of the soft soil layer, and t is the t value. p The time for primary consolidation completion is given by t, and the time for secondary consolidation settlement is given by t. Here, t represents the time corresponding to the desired secondary consolidation settlement S2.

[0028] When calculating the post-construction settlement of a box culvert, the parameters in the formula for calculating the secondary consolidation settlement S2 are the design parameters of the box culvert; when calculating the post-construction settlement of a roadbed, the parameters in the formula for calculating the secondary consolidation settlement S2 are the design parameters of the roadbed.

[0029] Post-construction settlement calculation sub-step S13, based on the principal consolidation settlement S t Calculation of post-consolidation settlement S2 and secondary consolidation settlement S p .

[0030] Specifically, according to formula S p =S t +S2-S cp Calculate the post-construction settlement S p In the formula, S cp For construction period settlement, the construction period settlement S cp The determination is based on the principle of consolidation and seepage in saturated soil and the construction period.

[0031] When calculating the post-construction settlement of the box culvert, the main consolidation settlement S of the box culvert is calculated according to the design parameters of the box culvert and the calculation formula in the main consolidation settlement calculation sub-step S11. t Calculate the secondary consolidation settlement S2 of the box culvert according to the calculation formula in sub-step S12 of the secondary consolidation settlement calculation, and then calculate the secondary consolidation settlement S2 according to formula S2. p1 =S t +S2-S cp Calculate the post-construction settlement S of the box culvert p1 S in the formula t S1 represents the primary consolidation settlement of the box culvert, and S2 represents the secondary consolidation settlement. Furthermore, the post-construction settlement S... p1 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0032] When calculating the post-construction settlement of the roadbed, the principal consolidation settlement S of the roadbed is calculated according to the design parameters of the roadbed and the calculation formula in the principal consolidation settlement calculation sub-step S11. t Calculate the secondary consolidation settlement S2 of the roadbed according to the calculation formula in sub-step S12 of the secondary consolidation settlement calculation, and then calculate the secondary consolidation settlement S2 according to formula S2. p2 =S t +S2-S cp Calculate the post-construction settlement S of the roadbed p2 S in the formula t S1 represents the primary consolidation settlement of the roadbed, and S2 represents the secondary consolidation settlement. Furthermore, the post-construction settlement S... p2 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0033] In step S2, a transition section is set at the junction of the box culvert and the roadbed. The length of the transition section is calculated based on the post-construction settlement of the box culvert and the roadbed, and the settlement parameters of the box culvert and the roadbed are determined.

[0034] Specifically, the uneven settlement difference at the junction of the box culvert and the roadbed is set to be less than or equal to i%, where i is less than or equal to 1, and the length of the transition section L ≥ (S p2 -S p1) / i%.

[0035] When the box culvert and the roadbed are treated with the same soft soil treatment method,

[0036] In calculation step S1, when calculating the post-construction settlement of the box culvert, the soft soil treatment depth D1 of the box culvert is set; when calculating the post-construction settlement of the roadbed, the soft soil treatment depth D2 of the roadbed is set.

[0037] In step S2, a transition section is set at the junction of the box culvert and the roadbed, within the depth range of the soft soil treatment. The length of the transition section L ≥ (S p2 -S p1) / i%. Furthermore, the soft soil treatment depth D1 of the box culvert is defined as the thickness of the soft soil treatment at the box culvert, and the soft soil treatment depth D2 of the roadbed is defined as the thickness of the soft soil treatment at the roadbed.

[0038] The specific processing procedure is as follows:

[0039] (1) Design soft soil treatment for the box culvert and set the soft soil treatment depth D1 for the box culvert. According to the formula... Calculate the primary consolidation settlement S of the box culvert t Then follow the formula Calculate the secondary consolidation settlement S2 of the box culvert, and then apply the formula S p1 =S t +S2-S cp Calculate the post-construction settlement S of the box culvert p1 Post-construction settlement of box culvert S p1 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0040] (2) The same soft soil treatment method as that used for box culverts was adopted for the soft soil treatment design of the roadbed section, and the soft soil treatment depth D2 of the roadbed was set. According to the formula... Calculate the principal consolidation settlement S of the roadbed t Then follow the formula Calculate the secondary consolidation settlement S2 of the roadbed, and then apply the formula S p2 =S t +S2-S cp Calculate the post-construction settlement S of the roadbed p2 Post-construction settlement of the roadbed S p2 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0041] (3) Set the uneven settlement difference at the junction of the box culvert and the roadbed to be less than or equal to i%. At the junction of the box culvert and the roadbed, and within the soft soil treatment depth range, a transition section is set up with a length L ≥ (S). p2 -S p1) / i%. Furthermore, the soft soil treatment depth D1 of the box culvert is defined as the thickness of the soft soil treatment at the box culvert location, and the soft soil treatment depth D2 of the roadbed is defined as the thickness of the soft soil treatment at the roadbed location, such as... Figure 2 As shown.

[0042] When box culverts and roadbeds are treated with different soft soil treatment methods...

[0043] In step S2, a transition section is set at the junction of the box culvert and the roadbed, within the overload preloading range, and the length L of the transition section is ≥ (S p2 -S p1) / i%. Furthermore, the preloading height at the box culvert is set as h1, and the preloading height at the roadbed is set as h2, where h1 > h2.

[0044] The specific processing procedure is as follows:

[0045] (1) Design soft soil foundation treatment at the box culvert location, according to the formula Calculate the primary consolidation settlement S of the box culvert t Then follow the formula Calculate the secondary consolidation settlement S2 of the box culvert, and then apply the formula S p1 =S t +S2-S cp Calculate the post-construction settlement S of the box culvert p1 Post-construction settlement of box culvert S p1 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0046] (2) Design soft soil treatment for the subgrade section according to the formula. Calculate the principal consolidation settlement S of the roadbed t Then follow the formula Calculate the secondary consolidation settlement S2 of the roadbed, and then apply the formula S p2＝ S t +S2-S cp Calculate the post-construction settlement S of the roadbed p2 Post-construction settlement of the roadbed S p2 The settlement is less than or equal to the post-construction settlement allowed by the design specifications.

[0047] (3) Set the uneven settlement difference at the junction of the box culvert and the roadbed to be less than or equal to i%. A transition section shall be set at the junction of the box culvert and the roadbed within the surcharge preloading range, with a length L ≥ (S... p2 -S p1) / i%. Furthermore, the preloading height at the box culvert is set as h1, and the preloading height at the roadbed is set as h2, where h1 > h2.

[0048] As can be seen, in this embodiment, the post-construction settlement of the box culvert and the roadbed is first calculated, and then a transition section is set at the junction of the box culvert and the roadbed. The length of the transition section is calculated based on the post-construction settlement of the box culvert and the roadbed, and the settlement parameters of the box culvert and the roadbed are determined. Construction is carried out based on the settlement parameters of the box culvert and the roadbed, which can effectively reduce the settlement difference at the junction of the box culvert and the roadbed, reduce vehicle bounce and cracks caused by uneven settlement at the junction of the box culvert and the roadbed, improve the construction quality and safety of the road, and thus ensure the traffic comfort at the box culvert. This solves the problem in the prior art that uneven settlement difference at the junction of the culvert and the roadbed can easily reduce the quality of road construction.

[0049] In this embodiment, the soft soil treatment depth between the box culvert foundation and the roadbed foundation is adjusted according to the settlement parameters of the box culvert and the roadbed, or the preloading height of the box culvert and the roadbed is adjusted, so that the sections of the box culvert and the roadbed with different post-construction settlement control standards can transition smoothly. This method is simple to operate and has a good effect.

[0050] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0051] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for controlling settlement of road culverts on soft soil foundations, characterized in that, Includes the following steps: The calculation steps involve performing soft soil foundation treatment on the target object and calculating the post-construction settlement of the target object, wherein the target object includes: box culverts and roadbeds; The steps are as follows: a transition section is set at the junction of the box culvert and the roadbed; the length of the transition section is calculated based on the post-construction settlement of the box culvert and the post-construction settlement of the roadbed; and the settlement parameters of the box culvert and the roadbed are determined. When the box culvert and the roadbed are treated with the same soft soil treatment method, In the calculation steps, when calculating the post-construction settlement of the box culvert, the soft soil treatment depth D1 of the box culvert is set; when calculating the post-construction settlement of the roadbed, the soft soil treatment depth D2 of the roadbed is set. In the determination step, the transition section is set at the junction of the box culvert and the roadbed and within the range of soft soil treatment depth, and the soft soil treatment depth D1 of the box culvert is determined as the thickness of the soft soil treatment at the box culvert, and the soft soil treatment depth D2 of the roadbed is determined as the thickness of the soft soil treatment at the roadbed. When the box culvert and the roadbed are treated with different soft soil treatment methods, In the determination step, a transition section is set at the junction of the box culvert and the roadbed within the overload preloading range, and the preloading height at the box culvert is set as h1, and the preloading height at the roadbed is set as h2, wherein h1 > h2; The calculation steps further include: The primary consolidation settlement calculation sub-step calculates the primary consolidation settlement S based on the drainage distance, the average initial effective stress of the soil layer, and the additional effective stress. t ; The sub-step for calculating secondary consolidation settlement calculates the secondary consolidation settlement S2 based on the thickness of the soft soil layer, the completion time of primary consolidation, and the secondary consolidation settlement time. The post-construction settlement calculation sub-step is based on the main consolidation settlement S. t The post-consolidation settlement S2 was calculated in conjunction with the secondary consolidation settlement S2. p ; In the post-construction settlement calculation sub-step According to formula S p= S t +S2-S cp Calculate the post-construction settlement S p In the formula, S cp The construction period settlement S is the settlement during the construction period. cp Determined based on the principle of consolidated seepage in saturated soil and the construction period; In the post-construction settlement calculation sub-step The post-construction settlement S of the box culvert p1 Less than or equal to the post-construction settlement allowed by the design specifications; In the post-construction settlement calculation sub-step The post-construction settlement S of the roadbed p2 Less than or equal to the post-construction settlement allowed by the design specifications; In the determination step The uneven settlement difference at the junction of the box culvert and the roadbed is set to be less than or equal to i%, where i is less than or equal to 1; The length L of the transition section is greater than or equal to (S p2 -S p1 ) / i%.

2. The method for controlling settlement of road culverts on soft soil foundations according to claim 1, characterized in that, In the main consolidation settlement calculation sub-step According to the formula Calculate the principal consolidation settlement S t In the formula, C ˊ c The coefficient of compression in a one-dimensional consolidation test is given by H, where H is the drainage distance. σ is the average initial effective stress of the soil layer. c To add effective stress.

3. The method for controlling settlement of road culverts on soft soil foundations according to claim 1, characterized in that, In the sub-step of calculating secondary consolidation settlement According to the formula Calculate the secondary consolidation settlement S2; where C ˊ a Here, H is the subcompression coefficient, H is the thickness of the soft soil layer, and t is the t value. p t is the time for primary consolidation to complete, and t is the time for secondary consolidation to settle.

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