Composite structure wide-source cementing material retaining wall and construction method

Abstract

The invention provides a composite structure wide-source cementing material retaining wall and a construction method, and belongs to the field of geotechnical engineering.The construction method comprises the steps that a foundation pit is excavated under the current ground, a layer of impermeable geotechnical cloth is laid at the bottom of the foundation pit, the top of the foundation pit is filled with wide-source cementing materials, and then a wide-source cementing material layer is formed; the inner slope side of the wide-source cementing material layer is backfilled with soil to form roadbed filling soil, and the outer slope side of the wide-source cementing material layer is sequentially poured to form a strip-shaped foundation and a concrete protection panel; the top of the wide-source cementing material layer and the top of the concrete protection panel are poured to form a guardrail base, a retaining wall concrete guardrail is arranged on the top of the guardrail base, and a pavement structure is laid on the inner side of the guardrail base and located on the top of the wide-source cementing material layer and the roadbed filling soil. On the premise that the stability and durability of the retaining wall are met, local materials are fully utilized, synchronous construction with roadbed filling can be achieved, and therefore the green building purposes of being low in cost, short in construction period, low in carbon and environmentally friendly are achieved.

Description

Technical Field

[0001] The invention belongs to the field of geotechnical engineering, and in particular relates to a composite structure Guangyuan cementitious material retaining wall and a construction method. Background Art

[0002] At present, the common retaining wall materials in highway design are concrete, rubble concrete or stone masonry. The main problems are: first, the specifications have high requirements for the strength of concrete retaining walls and stone masonry retaining walls, which are mainly limited by durability requirements, and the actual strength of the prepared materials is relatively surplus. Second, the use of concrete and rubble stone strips and other materials for highway retaining walls is not environmentally friendly and has high costs. It is often the case that the excavated stones cannot meet the design requirements, and it is necessary to transport or purchase materials to build retaining walls, which is not conducive to engineering construction and increases investment, which is contrary to the green and environmentally friendly building concept advocated by the country. At the same time, a large amount of roadbed fill soil, soft soil, soft rock, construction waste, etc. are often encountered in the project. In some places, there are still a lot of industrial waste residues. These materials are often treated as waste materials and waste residues due to their poor engineering properties. They not only affect the local ecological environment and occupy arable land, but also increase disposal costs, which runs counter to the current design concept. How to make good use of these bad materials is an urgent problem to be solved.

[0003] The raw materials for construction projects, such as gravel, crushed stone, river pond silt, abandoned soil and slag, which are commonly found in nature, are collectively referred to as Guangyuan materials. The "Guangyuan materials" are modified or improved, and their particles are cemented to have a certain strength and cohesion. This kind of material with certain cementitious properties after physical and chemical modification is called "Guangyuan cementing material", hereinafter referred to as "cementing material". This kind of building that uses all or part of Guangyuan materials and Guangyuan cementing materials is called "Guangyuan material building".

[0004] The results of relevant binder strength tests (unconfined compression, triaxial, tensile, shear), crack tests (early cracking tests), durability tests (impermeability, shrinkage tests) and on-site process tests indicate that the modified roadbed soil (i.e. "binder") with a cement content of about 8% has relevant mechanical and physical properties that meet the design verification and durability requirements of general counter-weight retaining wall structures, and has the characteristics of moderate strength, easy construction, green environmental protection, and low cost, and can be used to construct fill roadbed retaining walls.

[0005] Although CN116180806A discloses a Guangyuan cementitious retaining wall support structure and construction method, this retaining wall can usually only adapt to the retaining of walls with small slopes, and cannot adapt well to the retaining requirements of roadbeds with large heights and steep slopes. Summary of the invention

[0006] The purpose of the present invention is to provide a composite structure Guangyuan binder retaining wall and a construction method, which can fully utilize local materials and be constructed simultaneously with roadbed filling under the premise of meeting the stability and durability of the retaining wall, so as to achieve the green construction goals of low cost, short construction period, low carbon and environmental protection; in addition, the wall slope is steeper than the general inclined retaining wall slope by rolling through the support formwork, and can be set nearly vertically, saving land, avoiding the appearance of inner corners on the inner side of the formwork, and facilitating the compaction of the Guangyuan binder.

[0007] In order to achieve the above-mentioned technical features, the purpose of the present invention is achieved as follows: a composite structure Guangyuan binder retaining wall and construction method, including excavating a foundation pit below the existing ground, laying a layer of anti-seepage geotextile at the bottom of the foundation pit, filling the top of the foundation pit with Guangyuan binder to form a Guangyuan binder layer, the inner slope side of the Guangyuan binder layer is backfilled to form a roadbed fill, and the outer slope side of the Guangyuan binder layer is cast to form a strip foundation and a concrete protection panel in sequence; the top of the Guangyuan binder layer and the concrete protection panel are cast to form a guardrail base, a retaining wall concrete guardrail is arranged on the top of the guardrail base, and a pavement structure is laid on the inner side of the guardrail base and on the top of the Guangyuan binder layer and the roadbed fill.

[0008] A drainage filter layer is provided in the transition between the Guangyuan binder layer and the roadbed fill.

[0009] The slope of the concrete protection panel is 1:n1; the slope of the lower binder layer inside the Guangyuan binder layer slope is 1:n3, and the slope of the lower binder layer is in the same direction as the slope of the concrete protection panel; the slope of the upper binder layer inside the Guangyuan binder layer slope is 1:n4, and the slope of the upper binder layer is in the opposite direction to the slope of the concrete protection panel; The bottom of the foundation pit adopts a reverse slope structure with a slope of 1:n2; The slope of the concrete protection panel is greater than the slope of the lower cementitious material layer; Then a counterweight composite structure Guangyuan cementitious material retaining wall is formed.

[0010] The slope direction of the inner side of the Guangyuan cementing material layer is opposite to the slope direction of the concrete protection panel, and the slope direction of the outer side of the Guangyuan cementing material layer is in the same direction as the slope of the concrete protection panel, and the slopes are equal; The bottom of the foundation pit adopts a slope structure with a slope of 1:n2; the slope of the bottom of the foundation pit is in the same direction as the slope of the inner side of the Guangyuan cementing material layer; The slope of the inner side of the Guangyuan cementing material layer is 1:n5; The slope of the concrete protection panel is 1:n1; Then a downward-sloping Guangyuan binder composite structure retaining wall is formed.

[0011] A plurality of groups of retaining wall drainage pipes arranged in a staggered manner are arranged inside the Guangyuan cementitious material layer along the height direction; and the retaining wall drainage pipes penetrate the concrete protection panel.

[0012] A foundation pit sealing layer is arranged at the top of the foundation pit and outside the strip foundation; A drainage ditch is provided at the bottom of the retaining wall; A retaining wall drainage hole is provided through the interior of the retaining wall concrete guardrail.

[0013] A step is arranged at the top of the Guangyuan binder layer and at the junction with the concrete protective panel.

[0014] A composite structure Guangyuan cement retaining wall and construction method thereof, comprising the following steps: Step 1, cleaning of the existing ground: Clean the existing ground and roll it to make its compaction degree meet the design requirements; Step 2, excavation of foundation pit: Measure and lay out the retaining wall, excavate the foundation pit, lay a layer of anti-seepage geotextile at the bottom of the foundation pit, fill the foundation part with Guangyuan cementing material, and construct the strip foundation; Step 3, filling construction of foundation pit: When the strip foundation concrete strength reaches the design value, backfill the foundation pit with Guangyuan cementing material, and pour concrete on the top of the pit to form a foundation pit sealing layer to seal the foundation pit; Step 4, set up a template: For the first time, set up the external support formwork along the wall, and lay the Guangyuan binder layer, drainage filter layer, and roadbed fill layer in layers, with a loose laying thickness of 30cm~40cm. Roll each part simultaneously to the designed compaction degree, and use a small roller to roll within 1m~2m of the external support formwork; During the paving process of Guangyuan binder and roadbed filling behind the wall, the retaining wall drainage pipe is buried simultaneously; Step 5, setting of steps: After the Guangyuan binder is paved to the top of the wall, a step with a size of h×h is manually trimmed on the top of the wall; Step 6, secondary template establishment: Remove the primary formwork and move it outwards 20cm~25cm to re-erect the formwork; Step 7, pouring of concrete protection panel: The wall surface formed by the Guangyuan binder layer is roughened, and then the concrete protection panel is poured. The last layer of panel concrete is poured together with the wall top concrete to strengthen the connection between the panel concrete, wall top concrete and Guangyuan binder; Step 8, Construction of retaining wall concrete guardrail and pavement structure: After the construction of the concrete protective panel and the wall top sealing concrete is completed, the guardrail base, retaining wall concrete guardrail and pavement structure are poured.

[0015] The compaction degree of the Guangyuan binder composite structure retaining wall formed by the Guangyuan binder layer is not less than 93%, and the 28d unconfined compressive strength is ≥2.5MPa. A small roller is used for rolling within 1m of the template, and the compaction degree of the roadbed fill is determined in accordance with the "Highway Roadbed Design Specifications"; The concrete protection panel is set with a reinforced concrete strip foundation. The thickness of the concrete protection panel is 20cm, and the slope is the same as the wall surface. The strength grade of the concrete is C25 or C30; A drainage hole is staggered up and down every 2 to 3 meters on the wall, and the drainage hole uses a steel-plastic drainage pipe; The longitudinal joints of the concrete protection panel are consistent with the length of the guardrail base and strip foundation segments. The Guangyuan cementing material layer, drainage filter layer, and roadbed fill layer are constructed in layers and continuously without joints. The interval time between layers is: less than 3 hours for continuous construction, 3 hours to 16 hours without construction, and more than 16 hours for construction.

[0016] The Guangyuan binder or soil sample: CBR is not less than 3%, the maximum particle size is less than 20mm, the content of particles less than 0.075mm is not more than 40%, the organic matter content is ≤5%, and the moisture content of the bare soil is greater than 4% to 5% of the moisture content of the binder; Guangyuan binder: compaction degree ≥93%, moisture content ±2%, 7d shear index C value and Φ value meet the design requirements.

[0017] The present invention has the following beneficial effects: 1. The present invention adheres to the concept of "suitable materials for suitable structures, suitable structures for suitable materials". On the one hand, it adapts to the material performance requirements of large-volume, low-stress and different structures by selecting appropriate material modifications. On the other hand, starting from the constitutive model, the design is improved to adapt to new materials, moving in opposite directions from both material and structure aspects, thereby achieving the goal of low-carbon, environmental protection and green construction.

[0018] 2. The Guangyuan binder for retaining walls of the present invention is prepared by modifying the roadbed fill by adding a small amount of gel material, which can be made from local materials and has a construction cost of 80% of that of the rubble concrete retaining wall, with obvious economic benefits.

[0019] 3. The present invention realizes the simultaneous rolling construction of the main structure of the Guangyuan material retaining wall, the drainage filter layer, and the roadbed filling. The main structure has no longitudinal joints. Compared with the traditional plain concrete retaining wall construction process, the construction period is effectively shortened.

[0020] 4. The present invention studies a new retaining wall concrete panel, which forms a complete water-sealing system with the foundation pit anti-seepage geotextile and the pavement structure to enhance the durability of the retaining wall.

[0021] 5. The counterweight retaining wall structure adopted in the present invention is formed by rolling with a supporting formwork. The wall slope is steeper than that of a general inclined retaining wall, which saves land and avoids the appearance of a negative angle on the inner side of the formwork, making it easier to compact the source material.

[0022] 6. The retaining wall of the present invention can meet the requirements of retaining wall support stability and durability, and can replace the general traditional gravity concrete and stone retaining walls. It can use local materials and shorten the construction period. It has obvious economic benefits, and also achieves the goal of green and low-carbon construction with less or even zero waste, and has significant social benefits.

[0023] 7. The present invention enhances the bite between the protective panel concrete and the Guangyuan binder retaining wall by setting a 30cm×30cm step on the top of the wall, thereby improving the overall stability and reducing the stress concentration on the top of the Guangyuan binder retaining wall.

[0024] 8. The present invention effectively prevents groundwater from soaking the retaining wall during construction and improves the durability of the Guangyuan binder retaining wall by setting an anti-seepage geotextile. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 This is a cross-sectional view of the first type of counterweight Guangyuan binder composite structure retaining wall of the present invention.

[0027] Figure 2 This is a cross-sectional view of the second inclined Guangyuan binder composite structure retaining wall of the present invention.

[0028] In the figure: pavement structure 1, existing ground 2, concrete protection panel 3, Guangyuan binder layer 4, retaining wall drain pipe 5, strip foundation 6, drainage filter layer 7, anti-seepage geotextile 8, drainage ditch 9, roadbed fill layer 10, wall top drain hole 11, guardrail base 12, retaining wall drain hole 13, retaining wall concrete guardrail 14, step 15, half-width roadbed 16, shoulder 17, foundation pit 18, foundation pit sealing layer 19, lower binder layer 20, upper binder layer 21. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0030] Embodiment 1: See also Figure 1The present embodiment provides a counterweight type Guangyuan binder composite structure retaining wall, including a foundation pit 18 excavated below the existing ground 2, a layer of anti-seepage geotextile 8 is laid at the bottom of the foundation pit 18, the top of the foundation pit 18 is filled with Guangyuan binder to form a Guangyuan binder layer 4, the inner slope side of the Guangyuan binder layer 4 is backfilled to form a roadbed fill 10, and the outer slope side of the Guangyuan binder layer 4 is cast to form a strip foundation 6 and a concrete protection panel 3 in sequence; the top of the Guangyuan binder layer 4 and the concrete protection panel 3 are cast to form a guardrail base 12, and a retaining wall concrete guardrail 14 is arranged on the top of the guardrail base 12, and a pavement structure 1 is laid on the inner side of the guardrail base 12 and on the top of the Guangyuan binder layer 4 and the roadbed fill 10. By adopting the above-mentioned retaining wall, on the premise of meeting the stability and durability of the retaining wall, it is possible to fully utilize local materials and simultaneously construct with the roadbed fill, thereby achieving the green construction goals of low cost, short construction period, low carbon and environmental protection; in addition, the wall slope is steeper than the general inclined retaining wall slope by rolling through the support formwork, and can be set nearly vertically, saving land, avoiding the appearance of negative angles on the inner side of the formwork, and facilitating the compaction of the Guangyuan binder.

[0031] Furthermore, a drainage filter layer 7 is provided in transition between the Guangyuan cementing material layer 4 and the roadbed fill 10. The drainage filter layer 7 can effectively prevent the retaining wall drain pipe 5 from being blocked.

[0032] Furthermore, the slope of the concrete protection panel 3 is 1:n1; the slope of the lower binder layer 20 inside the slope of the Guangyuan binder layer 4 is 1:n3, and the slope of the lower binder layer 20 is in the same direction as the slope of the concrete protection panel 3; the slope of the upper binder layer 21 inside the slope of the Guangyuan binder layer 4 is 1:n4, and the slope of the upper binder layer 21 is opposite to the slope of the concrete protection panel 3. The above-mentioned slope setting further forms a counterweight Guangyuan binder composite structure retaining wall, which ensures the overall structural stability of the retaining wall.

[0033] Furthermore, the bottom of the foundation pit 18 adopts a reverse slope structure, and the slope is 1:n2; the above-mentioned slope plays a reaction force role, thereby enhancing the support stability of the bottom of the Guangyuan binder layer 4.

[0034] Furthermore, the slope of the concrete protection panel 3 is greater than the slope of the lower binder layer 20 .

[0035] Furthermore, multiple groups of staggered retaining wall drainage pipes 5 are arranged inside the Guangyuan cementing material layer 4 along the height direction; and the retaining wall drainage pipes 5 penetrate the concrete protection panel 3. The retaining wall drainage pipes 5 can be used for water supply and drainage of the retaining wall. A 110mm drainage hole is staggered up and down every 2 to 3 meters on the wall body. The drainage holes use steel-plastic drainage pipes to prevent construction rolling damage.

[0036] Furthermore, a foundation pit sealing layer 19 is provided at the top of the foundation pit 18 and outside the strip foundation 6. The foundation pit sealing layer 19 can be used to effectively seal the top of the foundation pit 18.

[0037] Further, the bottom of the retaining wall is provided with a drainage ditch 9. The drainage ditch 9 can be used for subsequent drainage of the bottom of the retaining wall.

[0038] Furthermore, a step 15 is provided at the top of the Guangyuan binder layer 4 and at the junction with the concrete protection panel 3 .

[0039] Preferably, a retaining wall drainage hole 13 is provided through the interior of the retaining wall concrete guardrail 14 .

[0040] Embodiment 2: See also Figure 1 The present invention provides a construction method of a counterweight Guangyuan cementing material composite structure retaining wall, comprising the following steps: Step 1, cleaning of existing ground 2: Clean the existing ground 2 and roll the ground to make its compaction degree meet the design requirements; Step 2, excavation of foundation pit 18: Measure and lay out the retaining wall, excavate the foundation pit 18, lay a layer of anti-seepage geotextile 8 at the bottom of the foundation pit 18, fill the foundation part with Guangyuan cementing material, and construct the strip foundation 6; Step 3, filling construction of foundation pit 18: When the concrete strength of the strip foundation 6 reaches the design value, the foundation pit 18 is backfilled with Guangyuan cement, and concrete is poured on the top of the pit to form a foundation pit sealing layer 19 to seal the foundation pit; Step 4, set up a template: For the first time, set up the external support formwork along the wall, and lay the Guangyuan binder layer 4, drainage filter layer 7, and roadbed fill layer 10 in layers, with a loose laying thickness of 30cm~40cm. Roll each part simultaneously to the designed compaction degree, and use a small roller to roll within 1m~2m of the external support formwork; During the paving process of Guangyuan cementing material and roadbed filling behind the wall, the retaining wall drainage pipe 5 is buried synchronously; Step 5, setting of step 15: After the Guangyuan binder is paved to the top of the wall, a step 15 with a size of h×h on the top of the wall is manually trimmed; Step 6, secondary template establishment: Remove the primary formwork and move it outwards 20cm~25cm to re-erect the formwork; Step 7, pouring of concrete protection panel 3: The wall surface formed by the Guangyuan binder layer 4 is roughened, and then the concrete protection panel 3 is poured. The last layer of panel concrete is poured integrally with the wall top concrete to strengthen the connection between the panel concrete, the wall top concrete and the Guangyuan binder; Step 8, construction of retaining wall concrete guardrail 14 and pavement structure 1: After the construction of the concrete protection panel 3 and the wall top sealing concrete is completed, the guardrail base 12, the retaining wall concrete guardrail 14 and the pavement structure 1 are poured.

[0041] Furthermore, the compaction degree of the Guangyuan binder composite structure retaining wall formed by the Guangyuan binder layer 4 is not less than 93%, the 28d unconfined compressive strength is ≥2.5MPa, a small roller is used for rolling within 1m of the template, and the compaction degree of the roadbed fill is determined in accordance with the "Highway Roadbed Design Code" JTG D30-2015.

[0042] Further, the concrete protection panel 3 is provided with a reinforced concrete strip foundation 6, the thickness of the concrete protection panel 3 is 20 cm, the slope is the same as the wall surface, and the strength grade of the concrete is C25 or C30; Further, a drainage hole is staggered up and down every 2 to 3 meters on the wall body, and the drainage hole adopts a steel-plastic drainage pipe. The arrangement of the drainage holes can achieve good drainage purpose.

[0043] Furthermore, the longitudinal joints of the concrete protection panel 3 are consistent with the length of the guardrail base 12 and the strip foundation 6, and the Guangyuan cementing material layer 4, the drainage filter layer 7, and the roadbed fill layer 10 are constructed in layers without joints. Through the above arrangement, the structural stability of the concrete protection panel 3 is guaranteed.

[0044] Furthermore, the inter-layer interval time is: continuous construction for less than 3 hours, no construction for 3 hours to 16 hours, and construction for more than 16 hours. The construction quality is guaranteed by the above inter-layer construction interval time.

[0045] Furthermore, the Guangyuan binder or soil sample has: CBR not less than 3%, maximum particle size less than 20mm, content less than 0.075mm not more than 40%, organic matter content ≤5%, and moisture content of the bare soil greater than 4% to 5% of the moisture content of the binder. The above material properties ensure the structural strength of the subsequent Guangyuan binder composite structure retaining wall.

[0046] Furthermore, Guangyuan binder: compaction degree ≥ 93%, moisture content ± 2%, 7d shear index C value and Φ value meet the design requirements.

[0047] Furthermore, the nominal diameter of the steel-plastic drain pipe is 90mm, the outer diameter of the pipe is 110mm, and the ring stiffness is not less than 6.4MPa, thereby ensuring its overall structural strength and stability and preventing damage to the pipe body during the rolling process.

[0048] Embodiment 3: See also Figure 2 The present embodiment provides a slope-inclined Guangyuan binder composite structure retaining wall, comprising a foundation pit 18 excavated below the existing ground 2, a layer of anti-seepage geotextile 8 laid at the bottom of the foundation pit 18, Guangyuan binder filled on the top of the foundation pit 18 to form a Guangyuan binder layer 4, the inner slope side of the Guangyuan binder layer 4 is backfilled to form a roadbed fill 10, and the outer slope side of the Guangyuan binder layer 4 is cast to form a strip foundation 6 and a concrete protection panel 3 in sequence; the top of the Guangyuan binder layer 4 and the concrete protection panel 3 are cast to form a guardrail base 12, and a retaining wall concrete guardrail 14 is arranged on the top of the guardrail base 12, and a pavement structure 1 is laid on the inner side of the guardrail base 12 and on the top of the Guangyuan binder layer 4 and the roadbed fill 10. The slope direction of the inner side of the Guangyuan binder layer 4 is opposite to the slope direction of the concrete protection panel 3, and the slope direction of the outer side of the Guangyuan binder layer 4 is in the same direction as the slope of the concrete protection panel 3, and the slopes are equal. The inclined Guangyuan binder retaining wall of the present invention has obvious advantages, and is more conducive to the on-site construction of the retaining wall and the physical quality control; and under the premise of meeting the stability and durability of the retaining wall, it can fully utilize local materials and can be constructed synchronously with the roadbed filling, thereby achieving the goal of green construction with low cost, short construction period, low carbon and environmental protection. Compared with the inclined binder retaining wall and the counterweight binder retaining wall, the inclined binder retaining wall has obvious advantages: the cross-section of its main structure is more regular than the counterweight type, which can effectively avoid stress concentration.

[0049] Furthermore, a drainage filter layer 7 is provided in transition between the Guangyuan cementing material layer 4 and the roadbed fill 10. The drainage filter layer 7 can effectively prevent the retaining wall drain pipe 5 from being blocked.

[0050] Furthermore, the bottom of the foundation pit 18 adopts a slope structure with a slope of 1:n2; the slope of the bottom of the foundation pit 18 is in the same direction as the slope of the inner side of the Guangyuan binder layer 4; the slope of the inner side of the Guangyuan binder layer 4 is 1:n5; the slope of the concrete protection panel 3 is 1:n1. Through the above-mentioned slope design, the cross-section of the main structure is more regular than the counterweight type, which can effectively avoid stress concentration; the wall surface is steeper than the inclined retaining wall and can be set nearly vertically. There is no negative angle on the inner side of the outer template, so the compaction blind area in the rolling range of the roller can be avoided, and the compaction degree of the wall can be effectively guaranteed; the wall back is inclined, which can make full use of the self-stability of the binder, so that each layer is laid in a fixed order of binder → drainage filter layer → roadbed fill, which is conducive to strengthening the interface connection and binder compaction.

[0051] Furthermore, multiple groups of staggered retaining wall drainage pipes 5 are arranged inside the Guangyuan cementing material layer 4 along the height direction; and the retaining wall drainage pipes 5 penetrate the concrete protection panel 3. The retaining wall drainage pipes 5 can be used for water supply and drainage of the retaining wall. A 110mm drainage hole is staggered up and down every 2 to 3 meters on the wall body. The drainage holes use steel-plastic drainage pipes to prevent construction rolling damage.

[0052] Furthermore, a foundation pit sealing layer 19 is provided at the top of the foundation pit 18 and outside the strip foundation 6. The foundation pit sealing layer 19 can be used to effectively seal the top of the foundation pit 18.

[0053] Further, the bottom of the retaining wall is provided with a drainage ditch 9. The drainage ditch 9 can be used for subsequent drainage of the bottom of the retaining wall.

[0054] Furthermore, a step 15 is provided at the top of the Guangyuan binder layer 4 and at the junction with the concrete protection panel 3 .

[0055] Preferably, a retaining wall drainage hole 13 is provided through the interior of the retaining wall concrete guardrail 14 .

[0056] Embodiment 4: See also Figure 2 The present invention provides a construction method of a tilted Guangyuan cementing material composite structure retaining wall, comprising the following steps: Step 1, cleaning of existing ground 2: Clean the existing ground 2 and roll the ground to make its compaction degree meet the design requirements; Step 2, excavation of foundation pit 18: Measure and lay out the retaining wall, excavate the foundation pit 18, lay a layer of anti-seepage geotextile 8 at the bottom of the foundation pit 18, fill the foundation part with Guangyuan cementing material, and construct the strip foundation 6; Step 3, filling construction of foundation pit 18: When the concrete strength of the strip foundation 6 reaches the design value, the foundation pit 18 is backfilled with Guangyuan cement, and concrete is poured on the top of the pit to form a foundation pit sealing layer 19 to seal the foundation pit; Step 4, set up a template: For the first time, set up the external support formwork along the wall, and lay the materials in layers in the order of Guangyuan binder layer 4, drainage filter layer 7, and roadbed fill layer 10, with a loose laying thickness of 30cm~40cm. Roll each part simultaneously to the designed compaction degree, and use a roller to roll within 1m~2m of the external support formwork; During the paving process of Guangyuan cementing material and roadbed filling behind the wall, the retaining wall drainage pipe 5 is buried synchronously; Step 5, setting of step 15: After the Guangyuan binder is paved to the top of the wall, a step 15 with a size of h×h on the top of the wall is manually trimmed; Step 6, secondary template establishment: Remove the primary formwork and move it outwards 20cm~25cm to re-erect the formwork; Step 7, pouring of concrete protection panel 3: The wall surface formed by the Guangyuan binder layer 4 is roughened, and then the concrete protection panel 3 is poured. The last layer of panel concrete is poured integrally with the wall top concrete to strengthen the connection between the panel concrete, the wall top concrete and the Guangyuan binder; Step 8, construction of retaining wall concrete guardrail 14 and pavement structure 1: After the construction of the concrete protection panel 3 and the wall top sealing concrete is completed, the guardrail base 12, the retaining wall concrete guardrail 14 and the pavement structure 1 are poured.

[0057] Furthermore, the compaction degree of the Guangyuan binder composite structure retaining wall formed by the Guangyuan binder layer 4 is not less than 93%, the 28d unconfined compressive strength is ≥2.5MPa, a roller is used for rolling within 1m of the template, and the compaction degree of the roadbed fill is determined in accordance with the "Highway Roadbed Design Code" JTG D30-2015.

[0058] Further, the concrete protection panel 3 is provided with a reinforced concrete strip foundation 6, the thickness of the concrete protection panel 3 is 20 cm, the slope is the same as the wall surface, and the strength grade of the concrete is C25 or C30; Further, a drainage hole is staggered up and down every 2 to 3 meters on the wall body, and the drainage hole adopts a steel-plastic drainage pipe. The arrangement of the drainage holes can achieve good drainage purpose.

[0059] Furthermore, the longitudinal joints of the concrete protection panel 3 are consistent with the length of the guardrail base 12 and the strip foundation 6, and the Guangyuan cementing material layer 4, the drainage filter layer 7, and the roadbed fill layer 10 are constructed in layers without joints. Through the above arrangement, the structural stability of the concrete protection panel 3 is guaranteed.

[0060] Furthermore, the inter-layer interval time is: continuous construction for less than 3 hours, no construction for 3 hours to 16 hours, and construction for more than 16 hours. The construction quality is guaranteed by the above inter-layer construction interval time.

[0061] Furthermore, the Guangyuan binder or soil sample has: CBR not less than 3%, maximum particle size less than 20mm, content less than 0.075mm not more than 40%, organic matter content ≤5%, and moisture content of the bare soil greater than 4% to 5% of the moisture content of the binder. The above material properties ensure the structural strength of the subsequent Guangyuan binder composite structure retaining wall.

[0062] Furthermore, Guangyuan binder: compaction degree ≥ 93%, moisture content ± 2%, 7d shear index C value and Φ value meet the design requirements.

[0063] Furthermore, the nominal diameter of the steel-plastic drain pipe is 90mm, the outer diameter of the pipe is 110mm, and the ring stiffness is not less than 6.4MPa, thereby ensuring its overall structural strength and stability and preventing damage to the pipe body during the rolling process.

[0064] Embodiment 5: See also Figure 2 , a new inclined Guangyuan binder composite structure retaining wall is designed by utilizing the material properties of Guangyuan binder. On the premise of meeting the stability and durability of the retaining wall, it can fully utilize local materials and be constructed simultaneously with the roadbed fill, thus achieving the green construction goal of low cost, short construction period, low carbon and environmental protection.

[0065] The main structure of the inclined retaining wall is filled with Guangyuan binder (roadbed improved soil). The structural dimensions of the wall can be determined according to the engineering properties of the binder and the retaining wall load calculation. Concrete protection panels are set on the retaining wall to improve its durability, forming a composite structure retaining wall. The retaining wall is constructed in two forms: the first time the formwork is supported on the wall, and the Guangyuan binder, drainage filter layer, and roadbed fill are constructed in layers with a loose thickness of 30cm and rolled synchronously. The main structure has no longitudinal joints. After the main structure of the retaining wall is completed, the formwork is removed. After the wall surface is roughened, the formwork is set for the second time, and the cast-in-place concrete protection panel of the retaining wall is poured to complete the construction of the composite structure retaining wall. Compared with the inclined binder retaining wall and the counter-weight binder retaining wall, the inclined binder retaining wall has obvious advantages: the cross-section of its main structure is more regular than that of the counter-weight type, which can effectively avoid stress concentration; the wall surface is steeper than the inclined retaining wall (it can be set nearly vertically), and there is no inner corner on the inner side of the outer formwork, so it can avoid the compaction blind area in the rolling range of the roller, effectively ensuring the compaction degree of the wall; the back of the wall is inclined, which can make full use of the self-stability of the binder, making it convenient for each layer to be laid in a fixed order of Guangyuan binder layer → drainage filter layer → roadbed fill, which is conducive to strengthening the interface connection and binder compaction.

[0066] Main design points: 1. The compaction degree of Guangyuan binder retaining wall shall not be less than 93%, and the 28d unconfined compressive strength shall be ≥2.5MPa. The roller shall be used for rolling within 1m of the template, and the compaction degree of the roadbed fill shall be determined in accordance with the "Highway Roadbed Design Code" (JTG D30-2015).

[0067] 2. The concrete protection panel is set up with a reinforced concrete strip foundation. The panel thickness is 20cm and the slope is the same as the wall. The strength grade of its concrete is C25 or C30. A 30cm×30cm step is set on the top of the wall to enhance the bite between the protection panel concrete and the Guangyuan binder retaining wall, improve the overall stability, and reduce the stress concentration on the top of the Guangyuan binder retaining wall.

[0068] 3. Prevent groundwater from soaking the retaining wall during construction and improve the durability of the Guangyuan binder retaining wall. The retaining wall foundation pit is fully covered with anti-seepage geotextile.

[0069] 4. A drainage and filter layer is set on the retaining wall, and a 110mm drainage hole is staggered up and down every 2 to 3 meters on the wall. The drainage holes use steel-plastic drainage pipes to prevent damage during construction.

[0070] 5. The longitudinal joints of the concrete protection panel are consistent with the length of the guardrail base and strip foundation segments. Guangyuan binder, drainage filter layer, and roadbed fill are constructed in layers and continuously without joints.

[0071] 6. The interval time between layers is: less than 3 hours for continuous construction, 3 hours to 16 hours for construction is not recommended considering the impact of upper layer rolling on the lower layer, and more than 16 hours for construction.

[0072] 7. Other structures such as drainage holes on top of walls, drainage holes on retaining wall guardrails, concrete guardrails on retaining walls, drainage ditches, etc. have the same design requirements as general retaining walls.

[0073] The main construction steps are as follows: The construction process is to erect the formwork twice, i.e., the Guangyuan binder and the concrete panel are constructed in steps. The construction sequence is: erect the inner formwork → lay the materials in layers (Guangyuan binder, drainage filter layer, roadbed fill) → roll in layers → repeat the above process until the top of the wall is filled → move the formwork outward 20cm → pour the concrete panel. The specific steps are: 1. Clean the ground and roll it to make its compaction degree meet the design requirements.

[0074] 2. Measure and lay out the retaining wall, excavate the foundation pit, lay a layer of anti-seepage geotextile at the bottom of the foundation pit, fill the foundation part with Guangyuan binder, and construct strip foundation.

[0075] 3. When the foundation concrete strength reaches the design value, backfill the foundation pit and pour 10cmC20 concrete on the top of the pit to seal the foundation pit.

[0076] 4. For the first time, set up the external support formwork along the wall, and lay the materials in layers in the order of binder → drainage filter layer → roadbed fill, with a loose laying thickness of 30cm. Roll each part simultaneously to the designed compaction degree, and use a roller to roll within 1m of the formwork.

[0077] 5. Drain pipes are buried simultaneously during the process of paving Guangyuan binder and roadbed fill behind the wall.

[0078] 6. After the Guangyuan binder is paved to the top of the wall, manually trim the 30×30cm steps on the top of the wall.

[0079] 9. Remove the formwork and move it outward 20cm to re-erect the formwork, roughen the wall surface, and then pour the concrete panel. The last layer of panel concrete is poured together with the wall top concrete to strengthen the connection between the panel concrete, wall top concrete and Guangyuan binder.

[0080] 10. After the construction of the concrete panel and the wall top sealing concrete is completed, the guardrail base and the pavement structure layer are poured.

[0081] Technical requirements for related materials: 1. Guangyuan binder or soil sample: CBR is not less than 3%, the maximum particle size is less than 20mm, the content of particles less than 0.075mm is not more than 40%, the organic matter content is ≤5%, and the moisture content of the bare soil is greater than 4% to 5% of the moisture content of the binder.

[0082] 2. Guangyuan binder: compaction degree ≥ 93%, optimum moisture content ±2%, 28d unconfined compressive strength ≥ 2.5MPa, 7d shear index C value and Φ value meet the design requirements.

[0083] 3. The nominal diameter of the steel skeleton plastic pipe is 90mm, the outer diameter of the pipe is 110mm, and the ring stiffness is not less than 6.4MPa.

Claims

1. A composite structure Guangyuan cement retaining wall and construction method, characterized in that: The invention comprises excavating a foundation pit (18) below the existing ground (2), laying a layer of anti-seepage geotextile (8) at the bottom of the foundation pit (18), filling the top of the foundation pit (18) with Guangyuan binder to form a Guangyuan binder layer (4), backfilling the inner slope side of the Guangyuan binder layer (4) to form a roadbed fill (10), and casting the outer slope side of the Guangyuan binder layer (4) to form a strip foundation (6) and a concrete protective panel (3) in sequence; casting the top of the Guangyuan binder layer (4) and the concrete protective panel (3) to form a guardrail base (12), a retaining wall concrete guardrail (14) is arranged on the top of the guardrail base (12), and a pavement structure (1) is laid on the inner side of the guardrail base (12) and on the top of the Guangyuan binder layer (4) and the roadbed fill (10).

2. According to claim 1, a composite structure Guangyuan cementitious material retaining wall and construction method, characterized in that: A drainage filter layer (7) is provided in transition between the Guangyuan cementing material layer (4) and the roadbed fill (10).

3. According to claim 1, a composite structure Guangyuan cement retaining wall and construction method, characterized in that: The slope of the concrete protection panel (3) is 1:n1; the slope of the lower binder layer (20) inside the slope of the Guangyuan binder layer (4) is 1:n3, and the slope of the lower binder layer (20) is in the same direction as the slope of the concrete protection panel (3); the slope of the upper binder layer (21) inside the slope of the Guangyuan binder layer (4) is 1:n4, and the slope of the upper binder layer (21) is in the opposite direction to the slope of the concrete protection panel (3); The bottom of the foundation pit (18) adopts a reverse slope structure, and the slope is 1:n2; The slope of the concrete protection panel (3) is greater than the slope of the lower binder layer (20); Then a counterweight composite structure Guangyuan cementitious material retaining wall is formed.

4. According to claim 1, a composite structure Guangyuan cementitious material retaining wall and construction method, characterized in that: The slope direction of the inner side of the Guangyuan cementing material layer (4) is opposite to the slope direction of the concrete protection panel (3), and the slope direction of the outer side of the Guangyuan cementing material layer (4) is in the same direction as the slope of the concrete protection panel (3), and the slopes are equal; The bottom of the foundation pit (18) adopts a slope structure with a slope of 1:n2; the slope of the bottom of the foundation pit (18) is in the same direction as the slope of the inner side of the Guangyuan cementing material layer (4); The slope of the inner side of the Guangyuan cementing material layer (4) is 1:n5; The slope of the concrete protection panel (3) is 1:n1; Then a downward-sloping Guangyuan binder composite structure retaining wall is formed.

5. According to claim 1, a composite structure Guangyuan cementitious material retaining wall and construction method, characterized in that: A plurality of groups of retaining wall drainage pipes (5) arranged in a staggered manner are arranged inside the Guangyuan cementing material layer (4) along the height direction; and the retaining wall drainage pipes (5) penetrate the concrete protection panel (3).

6. According to claim 1, a composite structure Guangyuan cementitious material retaining wall and construction method, characterized in that: A foundation pit sealing layer (19) is provided at the top of the foundation pit (18) and outside the strip foundation (6); A drainage ditch (9) is provided at the bottom of the retaining wall; A retaining wall drainage hole (13) is provided through the interior of the retaining wall concrete guardrail (14).

7. According to claim 1, a composite structure Guangyuan cementitious material retaining wall and construction method, characterized in that: A step (15) is provided at the top of the Guangyuan binder layer (4) and at the junction with the concrete protective panel (3).

8. The construction method of a composite structure Guangyuan binder retaining wall and construction method according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, cleaning of existing ground (2): Clean the existing ground (2) and roll the ground to make its compaction degree meet the design requirements; Step 2, excavation of foundation pit (18): Measure and lay out the retaining wall, excavate a foundation pit (18), lay a layer of anti-seepage geotextile (8) at the bottom of the foundation pit (18), fill the foundation part with Guangyuan cementing material, and construct a strip foundation (6); Step 3, filling construction of foundation pit (18): When the concrete strength of the strip foundation (6) reaches the design value, the foundation pit (18) is backfilled with Guangyuan cementing material, and concrete is poured on the top of the pit to form a foundation pit sealing layer (19) to seal the foundation pit; Step 4, set up a template: For the first time, an external support formwork is set along the wall surface, and a Guangyuan binder layer (4), a drainage filter layer (7), and a roadbed fill layer (10) are laid in layers, with a loose laying thickness of 30 cm to 40 cm. Each part is rolled simultaneously to a designed compaction degree, and a small roller is used to roll within 1 m to 2 m of the external support formwork; During the process of paving the Guangyuan binder and the roadbed fill behind the wall, a retaining wall drainage pipe (5) is buried simultaneously; Step 5, setting of steps (15): After the Guangyuan binder is paved to the top of the wall, a step with a size of h×h is manually trimmed on the top of the wall (15); Step 6, establishment of secondary template: Remove the primary formwork and move it outwards 20cm~25cm to re-erect the formwork; Step 7, pouring of concrete protection panel (3): The wall surface formed by the Guangyuan binder layer (4) is roughened, and then a concrete protective panel (3) is poured. The last layer of panel concrete is poured integrally with the wall top concrete to strengthen the connection between the panel concrete, the wall top concrete and the Guangyuan binder; Step 8, construction of retaining wall concrete guardrail (14) and pavement structure (1): After the construction of the concrete protection panel (3) and the wall top sealing concrete is completed, the guardrail base (12), the retaining wall concrete guardrail (14) and the road surface structure (1) are poured.

9. The construction method of a composite structure Guangyuan cement retaining wall and construction method according to claim 8, characterized in that: The compaction degree of the Guangyuan binder composite structure retaining wall formed by the Guangyuan binder layer (4) is not less than 93%, and the 28d unconfined compressive strength is ≥ 2.5MPa. A small roller is used for rolling within 1m of the template, and the compaction degree of the roadbed fill is determined in accordance with the "Highway Roadbed Design Code" (JTG D30-2015); The concrete protection panel (3) is provided with a reinforced concrete strip foundation (6), the concrete protection panel (3) is 20 cm thick, has the same slope as the wall surface, and the strength grade of the concrete is C25 or C30; A drainage hole is staggered up and down every 2 to 3 meters on the wall, and the drainage hole uses a steel-plastic drainage pipe; The longitudinal joints of the concrete protection panel (3) are consistent with the length of the sections of the guardrail base (12) and the strip foundation (6); the Guangyuan cementing material layer (4), the drainage filter layer (7), and the roadbed fill layer (10) are constructed in layers and continuously without joints; The interval time between layers is: less than 3 hours for continuous construction, 3 hours to 16 hours without construction, and more than 16 hours for construction.

10. The construction method of a composite structure Guangyuan cement retaining wall and construction method according to claim 8, characterized in that: The Guangyuan binder or soil sample: CBR is not less than 3%, the maximum particle size is less than 20mm, the content of particles less than 0.075mm is not more than 40%, the organic matter content is ≤5%, and the moisture content of the bare soil is greater than 4% to 5% of the moisture content of the binder; Guangyuan binder: compaction degree ≥93%, moisture content ±2%, 7d shear index C value and Φ value meet the design requirements.

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