阅读说明：本技术 一种路基施工工艺 (Roadbed construction process ) 是由 赵子材 岳飞飞 胡靖� 王建扬 陈磊 王志明 于 2020-07-09 设计创作，主要内容包括：本发明提供了一种路基施工工艺,包括以下步骤：步骤一、处理下承层；步骤二、在下承层上表面进行素土摊铺并整平；步骤三、在步骤二的下承层上画出整齐的标准面积方格网,按每平方米的水泥掺量在每个方格网内用人工将水泥撒布均匀,水泥掺入量应大于工艺理论设计量的0.5％～1％；步骤四、用路拌机进行素土与水泥的拌和；步骤五、整平并碾压素土水泥混合料。本发明先摊铺素土,然后在素土上撒布水泥,控制水泥的掺入量大于工艺理论设计量的0.5％～1％,再用路拌机拌和最后碾压,选用水泥改良土作为改良原料填筑路基,压实度、弯沉模量以及强度等都有良好的效果。(The invention provides a roadbed construction process, which comprises the following steps: step one, processing a lower bearing layer; step two, spreading and leveling plain soil on the upper surface of the lower bearing layer; step three, drawing a regular standard area square grid on the lower bearing layer in the step two, and manually spreading the cement uniformly in each square grid according to the cement mixing amount per square meter, wherein the cement mixing amount is 0.5-1% of the theoretical design amount of the process; step four, mixing plain soil and cement by using a road mixer; and step five, leveling and rolling the plain soil cement mixture. The invention firstly paves the plain soil, then spreads the cement on the plain soil, controls the doping amount of the cement to be 0.5% -1% of the theoretical design amount of the process, then mixes the cement by a road mixer and finally rolls the cement, selects the cement improved soil as the improved raw material to fill the roadbed, and has good effects of compactness, flexural modulus, strength and the like.)

1. A roadbed construction process is characterized by comprising the following steps:

step one, processing a lower bearing layer;

step two, spreading and leveling plain soil on the upper surface of the lower bearing layer;

step three, drawing a regular standard area square grid on the lower bearing layer in the step two, and manually spreading the cement uniformly in each square grid according to the cement mixing amount per square meter, wherein the cement mixing amount is 0.5-1% of the theoretical design amount of the process;

step four, mixing plain soil and cement by using a road mixer;

and step five, leveling and rolling the plain soil cement mixture.

2. The roadbed construction process according to claim 1, wherein the design amount of the doped cement is calculated as follows:

(1) after plain soil is filled to a roadbed and paved and leveled, calculating the mass of dry soil per square meter;

(2) and calculating the cement mixing amount per square meter according to the mass of the dry soil per square meter.

3. The roadbed construction process according to claim 2, wherein the calculation process in the step (2) is as follows:

after plain soil is filled to a roadbed and paved and leveled, a tester adopts a sand filling method to fill sand every 100m²The average dry density rho of the soil layer is measured at one point, the thickness h of the paved vegetable soil layer is measured by a measurer, and the mass G1 ═ h × rho of dry soil per square meter is calculated according to the data.

4. The roadbed construction process according to claim 2, wherein the cement mixing amount per square meter in the step (2) is calculated by the following steps:

calculating the theoretical cement mixing amount of each square meter of the soil layer according to the standard of 5 percent of the cement mixing amount and the mass of each square meter of dry soil: g2 ═ G1 × 5%.

5. The roadbed construction process of claim 1, wherein the actual mixing amount of the cement per square meter of soil layer is as follows: g3 ═ G1 × 5% × (100.5% to 101%).

6. The roadbed construction process of claim 1, wherein in the second step, the measured water content of the paved plain soil is controlled to be +/-2%.

7. The roadbed construction process of claim 1, wherein the road mixer mixes twice;

the cement is not required to be stirred to the bottom for the first time, and the cement is required to be left for 2-3 cm to prevent the cement from sinking and concentrating on the bottom and being not stirred;

the mixture is stirred to the bottom for the second time, and the mixture is stirred to the depth of about 1cm in the second stirring process so as to ensure that no plain soil interlayer exists between the upper layer and the lower layer and between the soil layers.

8. The roadbed construction process of claim 7, wherein after the first mixing is completed, the moisture content of the plain soil and cement mixture is checked.

9. The roadbed construction process of claim 1, wherein the roadbed mixer mixes from both sides to the middle of the roadbed, and the mixing overlap width is controlled to be more than 50 cm.

10. The roadbed construction process according to claim 1, wherein the road mixer detects the cement dosage during the mixing process, and if the dosage is insufficient, the cement is required to be timely distributed.

Technical Field

The invention relates to the field of roadbed construction, in particular to a roadbed construction process.

Background

The roadbed refers to a roadbed built under good geological, hydrological and climatic conditions. Existing roadbed filling basically uses local materials, and local silt is used as materials, so that although cost can be greatly reduced, the compaction degree hardly meets the requirement of the roadbed on the compaction degree, and once the compaction degree of the roadbed does not meet the requirement, the bearing capacity of the roadbed is insufficient, the structure of the whole pavement is damaged, rainwater or other free water can be possibly infiltrated, and the stability of the roadbed is reduced.

In view of the above, it is necessary to develop a roadbed construction process to solve the above problems.

Disclosure of Invention

The invention aims to provide a roadbed construction process, which comprises the steps of firstly paving plain soil, then spreading cement on the plain soil, controlling the doping amount of the cement to be more than 0.5-1% of the theoretical design amount of the process, then mixing by using a road mixer and finally rolling, and selecting cement improved soil as an improved raw material to fill a roadbed, wherein the roadbed has good effects of compactness, deflection modulus, strength and the like.

The technical scheme for realizing the purpose of the invention is as follows:

a roadbed construction process comprises the following steps:

step one, processing a lower bearing layer;

step two, spreading and leveling plain soil on the upper surface of the lower bearing layer;

step three, drawing a regular standard area square grid on the lower bearing layer in the step two, and manually spreading the cement uniformly in each square grid according to the cement mixing amount per square meter, wherein the cement mixing amount is 0.5-1% of the theoretical design amount of the process;

step four, mixing plain soil and cement by using a road mixer;

and step five, leveling and rolling the plain soil cement mixture.

As a further improvement of the present invention, the design amount calculation process for the blended cement is as follows:

(1) after plain soil is filled to a roadbed and paved and leveled, calculating the mass of dry soil per square meter;

(2) and calculating the cement mixing amount per square meter according to the mass of the dry soil per square meter.

As a further improvement of the invention, the mass calculation process of each square meter of dry soil in the step (1) is as follows:

after plain soil is filled to a roadbed and paved and leveled, a tester adopts a sand filling method to fill sand every 100m²The average dry density rho of the soil layer is measured at one point, the thickness h of the paved vegetable soil layer is measured by a measurer, and the mass G1 ═ h × rho of dry soil per square meter is calculated according to the data.

As a further improvement of the invention, the cement mixing amount per square meter in the step (2) is calculated by the following steps:

calculating the designed cement mixing amount of each square meter of the soil layer according to the standard of 5% of the cement mixing amount and the mass of each square meter of dry soil: g2 ═ G1 × 5%.

As a further improvement of the invention, the actual amount of cement incorporated per square meter of soil layer: g3 ═ G1 × 5% × (100.5% to 101%).

As a further improvement of the invention, in the second step, the actual measurement shows that the water content of the paved plain soil is controlled to be +/-2%.

As a further improvement of the invention, the road mixer mixes twice;

the cement is not required to be stirred to the bottom for the first time, and the cement is required to be left for 2-3 cm to prevent the cement from sinking and concentrating on the bottom and being not stirred;

the mixture is stirred to the bottom for the second time, and the mixture is stirred to the depth of about 1cm in the second stirring process so as to ensure that no plain soil interlayer exists between the upper layer and the lower layer and between the soil layers.

As a further improvement of the invention, after the first mixing is finished, the water content of the mixture of the plain soil and the cement is checked.

As a further improvement of the invention, the road mixer mixes from both sides to the middle of the roadbed, and the mixing overlap width is controlled to be more than 50 cm.

As a further improvement of the invention, the dosage of cement is detected in the mixing process, and if the dosage is insufficient, the cement needs to be timely distributed.

Compared with the prior art, the invention has the beneficial effects that:

the invention firstly paves the plain soil, then spreads the cement on the plain soil, controls the doping amount of the cement to be 0.5% -1% of the theoretical design amount of the process, then mixes the cement by a road mixer and finally rolls the cement, selects the cement improved soil as the improved raw material to fill the roadbed, and has good effects of compactness, flexural modulus, strength and the like.

Drawings

Fig. 1 is a flow chart of a roadbed construction process.

Detailed Description

The present invention is described in detail with reference to the embodiments shown in the drawings, but it should be understood that these embodiments are not intended to limit the present invention, and those skilled in the art should understand that functional, methodological, or structural equivalents or substitutions made by these embodiments are within the scope of the present invention.

The invention provides a roadbed construction process, which comprises the following steps:

step one, treatment of a lower bearing layer: the structure layer of the main bearing effect below the cement improved soil structure layer is a lower roadbed (lower bearing layer), the lower roadbed is filled with plain soil, the source of the plain soil is a soil borrowing field qualified in a soil test, the paved plain soil is required to be soil without turf, household garbage, tree roots, humus and the like, the lower bearing roadbed adopts a common roadbed filling construction process, namely horizontal layering, segmental filling and layered compaction, the compaction degree detection is more than 95%, the elevation, the width, the transverse slope and the like meet the highway engineering quality inspection and assessment standards (JTGF80/1-2017), and the lower bearing layer treatment process is as follows: before feeding the cement improved soil, rolling the surface of the lower bearing layer by using a road roller again, and if the surface layer is over-dry and the surface soil is loose, performing proper watering rolling; if the soil is over-wet and the spring phenomenon occurs, the measures of excavation and airing, soil replacement, cement doping and the like are adopted for processing, the surface of the lower bearing layer is flat and solid, the transverse drainage slope is not less than 2 percent, and the next procedure construction is carried out after the lower bearing layer is qualified.

Step two, spreading and leveling plain soil on the upper surface of the lower bearing layer; after the lower bearing layer is prepared to be qualified, carrying out cement soil construction, firstly carrying out lofting, releasing piles in the roadbed and filling side piles, wherein the piles or marks with pile numbers are arranged along the middle line or the side line of the designed roadbed, the line shapes and the like, each layer of filling is laid to be 30cm wider than the side line of the roadbed at each side, if the filling is not widened, the rolled soil is extruded outwards, the side line positions of the designed roadbed cannot be rolled and compacted, so that the rolling and the widening are carried out, and then a soil excavator is used for brushing the edge position of the roadbed according to the side pile lines to ensure that the edge of the roadbed after the side slope is trimmed has enough compaction. Adopt the square grid method, the required size of square grid of each car soil is calculated to operation team organization personnel according to dump truck's load capacity size, and the scene hangs the line and spills the lime line according to the size of confirming again, and dump truck transports the filler to the scene and unloads, and the strict square grid of drawing unloads, and the process of frame method is: and taking 5 multiplied by 6m in the square grids, selecting three values of 35cm, 37cm and 40cm according to the loose paving thickness of construction experience, carrying out test section construction, determining the final loose paving thickness by the test section, after finishing the rolling of the roadbed of the test section, detecting that all indexes meet the requirements, taking the average value of the measured loose paving thickness as a final loose paving thickness parameter, actually measuring the water content on site, controlling the water content to be +/-2%, turning over for airing when the water content is insufficient, and timely carrying out water distribution when the water content is insufficient. When the soil block is paved, firstly, a bulldozer is used for primary leveling, the filler is manually checked after the primary leveling, the soil block with the diameters of sundries and filler particles being larger than 100mm is cleared, then, a land leveler is used for secondary leveling, namely, the soil block is finely leveled, for areas with uneven surfaces and insufficient elevations, the land leveler or the manpower is used for filling, and the land leveler is used for fine leveling after the pre-pressing. The back layer of the fine plane should be flat and uniform in thickness.

Step three, drawing regular square grids with standard area on the lower bearing layer in the step two, manually spreading the cement in each square grid according to the cement mixing amount per square meter, and mixing the cementThe input amount is 0.5-1% of the theoretical design amount of the process. The design amount calculation process of the doped cement is as follows: (1) after plain soil is filled to a roadbed and paved and leveled, calculating the mass of dry soil per square meter; (2) and calculating the cement mixing amount per square meter according to the mass of the dry soil per square meter. The calculation process in the step (2) is as follows: after plain soil is filled to a roadbed and paved and leveled, a tester adopts a sand filling method to fill sand every 100m²And (2) measuring the average dry density rho of the soil layer at one point, measuring the thickness h of the paved vegetable soil layer by a measurer, and calculating the mass of dry soil per square meter according to the data, wherein G1 is h × rho, and the cement mixing amount per square meter in the step (2) is calculated according to the standard of 5% of the cement mixing amount and the mass of the dry soil per square meter, wherein G2 is G1 × 5%, and the actual cement mixing amount per square meter of the soil layer is G3 is G1 × 5% × (100.5% -101%).

Step four, mixing plain soil and cement by using a road mixer; immediately mixing the mixture by using a road mixer after ash distribution is finished, checking the water content of the mixture after mixing once, mixing the improved soil by using the road mixer, and keeping 2-3 cm of the mixture after the mixture is not stirred to the bottom for the first time so as to prevent the cement from sinking and concentrating on the bottom and not stirring; the mixture is stirred to the bottom for the second time, and the mixture is stirred to the depth of about 1cm when the mixture is stirred for ensuring that the upper layer and the lower layer are connected and no plain soil interlayer exists between soil layers. The mixing is carried out from two sides to the middle of the roadbed by the digging machine, and the mixing overlapping width is controlled to be more than 50 cm. During the mixing process of the excavator, a specially-assigned person is arranged to excavate and check the mixing depth, and the phenomena of interlayer and mixing leakage are strictly prohibited. After crushing and mixing for 5 times, the mixture is uniformly stirred by visual inspection, the color is consistent, no ash-mass gray strips exist, the cement is not accumulated, no plain soil layer exists in the mixture, no soil blocks larger than 10mm exist, the cement dosage is immediately detected, the EDTA titration method is adopted for rapid determination, and the detection frequency is 3 points of longitudinal sampling along the line according to the acceptance standard requirement. If the dosage is insufficient, cement needs to be timely scattered.

And step five, leveling and rolling the plain soil cement mixture. And after the mixing depth, the particle size of the mixture and the cement doping amount are detected to be qualified, and the water content reaches the optimal water content, leveling by using a grader, preparing a drainage slope according to design blocks, and longitudinally smoothing. The rolling process follows the principle of static pressure firstly, vibration secondly, light firstly, heavy secondly, fast firstly, slow secondly, and both sides firstly and middle firstly, the rolling process adopts two-movement and two-static secondly, and then the compaction degree is detected, if the detection result can not meet the design requirement, the repeated construction and detection of one-movement and one-static secondly are required. And recording the compaction thickness, the rolling times and the test results and comparing the results until the design requirements are met when one unit is constructed. After the rolling is finished, if the transverse slope and the longitudinal slope of the roadbed do not meet the design requirements, a grader is used for leveling again, the two sides of the roadbed are scraped to the center of the road, and a road arch is formed after leveling. When leveling, the mixture higher than the elevation should be scraped out of the road, and a thin layer patching phenomenon is forbidden. In the leveling process, any vehicle is strictly forbidden to pass, and non-construction personnel are forbidden to enter a construction site. The degree of compaction, flatness, etc. are checked.

Step six, roadbed renovation; the roadbed is filled to a designed height, the drainage cross slope, the flatness, the side slope and the like of the roadbed surface are renovated according to the specified gradient and road arch, the widened part is manually brushed and tamped in the renovation stage, and the gradient of the side slope is controlled by a gradient ruler. The slope shoulder edges are neat after slope collection, the curve is smooth, the slope surface is flat, and no floating slag exists.

And step seven, maintaining the roadbed surface, namely timely watering and maintaining after finishing, forming and final pressure detection are qualified, wherein watering times are determined according to weather and pavement moisture evaporation conditions, the surface is always kept wet, the maintenance period is not less than 7 days generally, traffic is sealed in the maintenance period, and vehicles except for watering vehicles are forbidden to pass, particularly heavy vehicles are forbidden to pass.

In the first to seventh steps of the invention, (1) the cement modified soil must be rolled and formed at one time, the cement modified soil cannot be stopped in the midway, the cement modified soil cannot be pressed again after being rolled and qualified, and the cement modified soil can be broken in the integrity after being initially set, so that the upper layer part is loose. (2) The detection of the mixture (the amount of the ash) needs to be timely, otherwise, the cement is hydrated, the soil structure is changed, and the detection value is greatly influenced. (3) The construction is that the subsection should not be overlong, when the subsection is more than 100 meters, the spreading cement can begin to mix after half an breadth is finished, so as to shorten the construction time. (4) The watering maintenance needs to be timely, and the surface is loose due to untimely watering. (5) In the construction process, the earthwork transport vehicle is suitable to adopt a small vehicle, and the construction vehicle is forbidden to avoid sharp bending on the constructed improved soil surface and damage the lower-layer improved soil. (6) When construction is carried out in summer in high-temperature weather, construction time needs to be reasonably arranged, and stirring is carried out in the hottest period of noon.

The invention finally selects 5% of cement mixing amount, because: the 3 percent cement mixing amount does not meet the design requirement, the 5 percent and 7 percent cement mixing amount meets the design requirement, the 5 percent cement mixing amount is selected comprehensively, the economy and the effectiveness are achieved, the engineering quality is ensured,

3 percent of cement mixing amount, 5 percent of cement mixing amount and 7 percent of cement mixing amount, and the experimental data are as follows:

3% cement dosage improved soil roadbed pavement deflection test detection report

3% cement dosage improved soil compaction degree detection report

Detection report of deflection test of 5% cement dosage improved soil roadbed pavement

5% cement dosage improved soil compaction degree detection report

Detection report of deflection test of 7% cement dosage improved soil roadbed pavement

7% cement dosage improved soil compaction degree detection report

The invention firstly paves the plain soil, then spreads the cement on the plain soil, controls the doping amount of the cement to be 0.5% -1% of the theoretical design amount of the process, then mixes and rolls by a road mixer, selects the cement improved soil as the improved raw material to fill the roadbed, and has good effects of compactness, flexural modulus, strength and the like.

The weathered red sandstone is easy to disintegrate, break and even muddle under the action of the atmospheric environment after being excavated and broken out, so that the size and the grain composition of the rock mass change along with the time process of the dry-wet cycle, and the physical properties of the rock mass also change. The red sandstone subjected to rainwater disintegration and expansion is exposed in the air after excavation, is easily disintegrated into small fragments under the repeated action of sunlight, atmosphere and particularly rainwater, the volume is slightly increased, the expansion rate is about 1-4%, and the disintegrated red sandstone is easy to form sludge under the mechanical and manual actions, wherein the strength of a soil body softened by the water is quickly reduced (the reduction rate is as high as about 40%). Secondly, the red sandstone has high water absorption, water permeability and difficult evaporation, and once the red sandstone is disintegrated or rolled into a fine particle shape, the water absorption of the red sandstone is enhanced, and a large number of the red sandstone reaches a saturated state; the red sandstone sandy soil is used as a roadbed filling material, the compaction degree of the red sandstone sandy soil can meet related requirements, but the soil body is easy to loosen after meeting water; the water evaporation of the red sandstone after water saturation under the irradiation of sunlight and the weathering effect is slow and can be completed only about 3 days, and the red sandstone soil body recombined after the low caking property is broken has extremely poor caking property and hardening property and is easy to loosen, and a block-shaped sample is difficult to obtain when the compactness is detected.

The cement improvement principle is that cement is doped into weathered red sandstone sandy soil, tricalcium silicate in the cement undergoes hydration reaction, the tricalcium silicate can generate cementation effect with soil particles which are easy to soften when meeting water in the hydration process, and a product in which C-S-H gel, calcium hydroxide and soil particles coexist is formed after the hydration effect, so that the compressive strength and the durability of the soil are obviously improved, and the water stability of the soil is improved.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative invention, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present invention is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art will be able to make the description as a whole, and the embodiments of the present invention may be combined as appropriate to form other embodiments understood by those skilled in the art.