阅读说明：本技术 采用片石挤密加筋垫层法处理新近填土路基的方法 (Method for treating recent road filling foundation by adopting rubble compaction reinforced cushion layer method ) 是由 邓媚 陈世京 罗降 覃承统 舒鑫 周立兰 于 2021-10-21 设计创作，主要内容包括：本发明公开了一种采用片石挤密加筋垫层法处理新近填土路基的方法,包括以下步骤：①将新近填土路基的厚软土层进行挖除,利用小型振捣机具振捣密实,对地基承载力进行检测；②检测合格后回填片石,形成片石层,回填片石后应用碎石填隙；③碾压密实后铺砌碎石层；④铺砌碎石层后再填入中粗砂,形成砂垫层；⑤在砂垫层上加铺两层钢塑复合格栅,每层钢塑复合格栅上回填硬土,并用震动压路机分层震动密实；⑥钢塑复合格栅铺设定位后,及时填土覆盖。本申请的方案能提高路基强度,保证路基稳定,防止不均匀沉降,且开挖范围较小,施工方便,投资较省,有效解决了新近填土路基的稳定问题。(The invention discloses a method for treating a recent road filling subgrade by adopting a rubble compaction reinforced cushion method, which comprises the following steps: firstly, excavating a thick and soft soil layer of a newly filled soil subgrade, compacting by using a small-sized vibrator to detect the bearing capacity of the subgrade; secondly, backfilling rubbles after the detection is qualified to form a rubble layer, and applying broken stones for gap filling after backfilling the rubbles; thirdly, paving a crushed stone layer after rolling compaction; fourthly, after the gravel layer is paved, medium coarse sand is filled into the gravel layer to form a sand cushion layer; paving two layers of steel-plastic composite grids on the sand cushion layer, backfilling hard soil on each layer of steel-plastic composite grid, and using a vibration road roller to carry out layered vibration compaction; sixthly, after the steel-plastic composite grating is laid and positioned, filling soil in time for covering. The scheme of this application can improve road bed intensity, guarantees that the road bed is stable, prevents inhomogeneous settlement, and the excavation scope is less, and construction convenience, the investment is more economized, has effectively solved the stable problem of road bed of filling up newly.)

1. A method for treating a recent road filling foundation by adopting a rubble compaction reinforced cushion method is characterized by comprising the following steps:

firstly, excavating a thick and soft soil layer of a newly filled soil subgrade, compacting by using a small-sized vibrator to detect the bearing capacity of the subgrade;

secondly, backfilling rubbles after the detection is qualified to form a rubble layer, and applying broken stones for gap filling after backfilling the rubbles;

thirdly, paving a crushed stone layer after rolling compaction;

fourthly, after the gravel layer is paved, medium coarse sand is filled into the gravel layer to form a sand cushion layer;

additionally paving two layers of steel-plastic composite grids on the sand cushion layer, backfilling hard soil on each layer of steel-plastic composite grid, and using a vibration road roller to carry out layered vibration compaction, wherein the compaction thickness is not less than 30cm, and the compaction degree is not less than 90%; the longitudinal stress direction of the installed and laid steel-plastic composite grating is vertical to the axis direction of the road, and the laying requirement is flat, and no crease and tension exist; overlapping two adjacent steel-plastic composite gratings by not less than 30cm, binding the two adjacent steel-plastic composite gratings by high-strength nylon ropes every 0.8-1.5 m along the longitudinal direction of a road, and fixing the two adjacent steel-plastic composite gratings on a soil layer by U-shaped nails;

and finally, after the steel-plastic composite grating is laid and positioned, filling soil in time for covering, wherein the exposure time is not more than 48 hours, a flow process method of paving and backfilling is adopted, specifically, the filling material is paved on two sides firstly, the grating is fixed, then the grating is pushed to the middle part, the rolling sequence is that the two sides are arranged first and then the middle is arranged, the maximum thickness between the steel-plastic composite grating and the wheels of the construction machine is not less than 15 cm, and the compaction degree is not less than 95%.

2. The method for treating the recent road subgrade by adopting the rubble compaction reinforced cushion method according to claim 1, which is characterized in that in the step five, the filling requirement of hard soil is filled between the two steel-plastic composite grids: the internal friction angle is not less than 30 degrees, the plasticity index is not more than 20, and hard and sharp stones cannot be doped to avoid damaging the steel-plastic composite grating.

3. The method of treating a fresh road subgrade using the rubble compaction reinforcement underlayment method of claim 1, wherein the depth of the thick soft soil layer is not more than 4 meters.

4. The method for treating a recent road subgrade by adopting the rubble compaction reinforcement cushion method according to claim 1, wherein each linear meter of the steel-plastic composite grids requires the following tensile yield force: the cross section direction is more than or equal to 100KN/m, and the other direction is more than or equal to 80 KN/m; the yield elongation is less than or equal to 3 percent.

5. The method for treating the recent road filling foundation by adopting the rubble compaction reinforced cushion layer method according to claim 1, wherein the backfill thickness of the rubble layer is 80-150 cm, the rubble layer is compacted by vibration of a vibration road roller, the compaction thickness is 30-50 cm, and the compaction degree is not less than 93%.

6. The method for treating the recent road filling foundation by adopting the rubble compaction reinforced cushion layer method according to claim 1, wherein the backfill thickness of the rubble layer is 20-60 cm, the rubble layer is compacted by vibration of a vibration road roller, the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

7. The method for treating the recent road filling foundation by adopting the rubble compaction reinforced cushion layer method according to claim 1, wherein the backfill thickness of the sand cushion layer is 30-90 cm, the sand cushion layer is compacted by vibration of a vibration road roller, the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

8. The method for treating a recent road bed by adopting the rubble compaction reinforcement cushion method according to claim 1, wherein in the step of digging out a thick soft soil layer of the recent road bed, side slopes with different gradients are formed on two sides of a roadbed, the filled soil is in a loose state and is easy to collapse to cause side slope instability, and slope placing or sand bag piling means are adopted during construction to ensure the safety of adjacent buildings and construction.

9. The method for treating a recent road subgrade by adopting the rubble compaction reinforcement cushion method according to claim 1, wherein in the fifth step and the sixth step, in order to prevent the damage of construction vehicles, the steel-plastic composite grid which is not compacted can not allow the vehicles to run on the grid.

Technical Field

The invention relates to the technical field of road foundation construction, in particular to a method for treating a recent road filling foundation by adopting a rubble compaction reinforcement cushion method.

Background

In urban road construction, the situation that the roadbed is newly filled with earth is often encountered, and generally the situation is caused by the situation that a road is built in a construction area after the field is leveled. Recent filling generally has the characteristics of lower strength, higher compressibility, looser and the like, and roads constructed on the roadbed often have the problems that the strength, deformation and later-stage uneven settlement of the roadbed cannot meet the design requirements, so that measures need to be taken for roadbed treatment. For the recent filling, the filling method is generally adopted to treat the newly filled soil with smaller thickness, and the method such as sand pile, lime pile, chemical grouting or preloading is generally adopted to treat the newly filled soil with larger thickness.

The surrounding buildings of the urban road are dense, the construction working surface is small, the construction period is short, and for soil layers with 7 meters, 8 meters or even deeper, if the soil layers are treated by methods such as sand piles, lime piles, chemical grouting or preloading, the method has limitations; if the method of replacing and filling is adopted for processing, the slope is not placed at enough positions, the safety of buildings at two sides can be endangered by slope placing, and the life of surrounding residents can be influenced during construction.

Disclosure of Invention

The method for treating the recent soil filling subgrade by adopting the rubble compaction reinforcement cushion method can improve the strength of the subgrade, ensure the stability of the subgrade, prevent uneven settlement, reduce the excavation range, facilitate construction and save investment, and effectively solves the problem of stability of the recent soil filling subgrade by adopting local replacement filling, rubble throwing and silt squeezing, laying of a rubble cushion and increasing of geogrids.

The specific scheme is as follows:

a method for treating a recent road filling foundation by adopting a rubble compaction reinforced cushion method comprises the following steps:

firstly, excavating a thick and soft soil layer of a newly filled soil subgrade, compacting by using a small-sized vibrator to detect the bearing capacity of the subgrade;

secondly, backfilling rubbles after the detection is qualified to form a rubble layer, and applying broken stones for gap filling after backfilling the rubbles;

thirdly, paving a crushed stone layer after rolling compaction;

fourthly, after the gravel layer is paved, medium coarse sand is filled into the gravel layer to form a sand cushion layer;

additionally paving two layers of steel-plastic composite grids on the sand cushion layer, backfilling hard soil on each layer of steel-plastic composite grid, and using a vibration road roller to carry out layered vibration compaction, wherein the compaction thickness is not less than 30cm, and the compaction degree is not less than 90%; the longitudinal stress direction of the installed and laid steel-plastic composite grating is vertical to the axis direction of the road, and the laying requirement is flat, and no crease and tension exist; overlapping two adjacent steel-plastic composite gratings by not less than 30cm, binding the two adjacent steel-plastic composite gratings by high-strength nylon ropes every 0.8-1.5 m along the longitudinal direction of a road, and fixing the two adjacent steel-plastic composite gratings on a soil layer by U-shaped nails;

and finally, after the steel-plastic composite grating is laid and positioned, filling soil in time for covering, wherein the exposure time is not more than 48 hours, a flow process method of paving and backfilling is adopted, specifically, the filling material is paved on two sides firstly, the grating is fixed, then the grating is pushed to the middle part, the rolling sequence is that the two sides are arranged first and then the middle is arranged, the maximum thickness between the steel-plastic composite grating and the wheels of the construction machine is not less than 15 cm, and the compaction degree is not less than 95%.

It needs to be further explained that, in the fifth step, the filling requirement of the hard soil backfilled between the two steel-plastic composite grids is as follows: the internal friction angle is not less than 30 degrees, the plasticity index is not more than 20, and hard and sharp stones cannot be doped to avoid damaging the steel-plastic composite grating.

It is further noted that the depth of the thick soft soil layer does not exceed 4 meters.

It should be further noted that each linear meter of the steel-plastic composite grating requires the following tensile yield force: the cross section direction is more than or equal to 100KN/m, and the other direction is more than or equal to 80 KN/m; the yield elongation is less than or equal to 3 percent.

The backfill thickness of the rubble layer is 80-150 cm, and the rubble layer is compacted by vibration of a vibration road roller, wherein the compaction thickness is 30-50 cm, and the compaction degree is not less than 93%.

The backfill thickness of the crushed stone layer is 20-60 cm, and the crushed stone layer is compacted by vibration of a vibration road roller, wherein the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

The sand cushion layer is backfilled to 30-90 cm thick, and then is compacted through vibration of a vibration road roller, wherein the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

It should be further explained that, in the process of excavating the thick and soft soil layer of the newly filled soil roadbed, side slopes with different slopes are formed on two sides of the roadbed, the filled soil is in a loose state and is easy to collapse to cause side slope instability, and a slope placing or sand bag piling means is adopted during construction to ensure the safety of adjacent buildings and construction.

It should be further noted that in the fifth step and the sixth step, in order to prevent the damage of the construction vehicle, the uncompacted steel-plastic composite grid does not allow the vehicle to run on the grid.

It needs to be further explained that, the composite steel-plastic grid is adopted in the scheme of the application, because the composite steel-plastic grid is a reinforced material and has six basic functions of reinforcement, isolation, protection, seepage prevention, filtration and drainage. The steel-plastic composite grating is used for treating the bad soil subgrade, the vertical deformation of the upper filler is diffused to the horizontal direction through the steel-plastic composite grating, so that the shear deformation capacity of the upper filler can be fully exerted, the bearing capacity of the surface of the bad soil subgrade is greatly increased, the surface pressure is correspondingly reduced, and the purpose of improving the bearing capacity is achieved. Meanwhile, the grids are connected in a crisscross mode, so that local sinking of the filler can be prevented, and uneven settlement of the roadbed can be reduced to the maximum extent.

The invention has the following advantages:

1. according to the method for treating the recent soil filling subgrade by adopting the rubble compaction reinforcement cushion method, the recent soil filling subgrade is treated by adopting local replacement filling, rubble throwing and silt squeezing, paving of a broken stone cushion and increasing of geogrids, so that the strength of the subgrade can be improved, the stability of the subgrade is ensured, uneven settlement is prevented, the excavation range is small, the construction is convenient, the investment is saved, and the problem of stability of the recent soil filling subgrade is effectively solved;

2. the bearing capacity of the foundation is greatly improved, a stable roadbed layer is formed through the silt squeezing effect of the flaky stones, and the bearing capacity of the foundation is improved;

3. the compaction effect is good, and after the stone sheet compaction reinforced cushion layer method is adopted, due to the constraint effect of the steel-plastic composite grating, the filler is easy to compact, the surface is smooth, and the tracks of the road roller are not obvious. The road section without the steel-plastic composite grating is wavy in surface, the road roller has deep and wide wheel tracks and tends to expand from two sides, and the compaction effect is poor;

4. the engineering quantity is small, the replacement and filling depth is small, the temporary excavation slope can be steep, the occupied area is small, the engineering quantity is reduced, and the construction speed is accelerated;

5. the roadbed stability is good, and the phenomena of slippage, collapse, subsidence and the like can be effectively prevented by a rubble silt-squeezing reinforced cushion layer method;

6. the method for treating the recent road filling foundation by adopting the rubble compaction reinforced cushion method is simple and convenient to construct and easy to popularize;

7. the method for treating the recent road filling foundation by adopting the rubble compaction reinforced cushion method has the advantages of small engineering amount and low capital saving.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

FIG. 1 is a schematic structural diagram of a roadbed obtained by a method for treating a recent road bed by adopting a rubble compaction reinforced cushion method;

wherein: 1-a rubble layer, 2-a rubble layer, 3-a sand cushion layer, 4-a steel-plastic composite grid, 5-hard soil, 6-a side slope and 7-an in-situ flat line.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, a method for treating a recent road-fill subgrade by adopting a rubble compaction reinforcement cushion method comprises the following steps:

firstly, excavating a thick and soft soil layer of a newly filled soil roadbed (measuring an in-situ leveling line 7), compacting by using a small-sized vibrating machine, and detecting the bearing capacity of the roadbed;

secondly, backfilling the rubbles after the detection is qualified to form a rubble layer 1, and applying broken stones to fill the gaps after the rubbles are backfilled;

thirdly, paving a crushed stone layer 2 after rolling compaction;

fourthly, after the gravel layer is paved, medium coarse sand is filled into the gravel layer to form a sand cushion layer 3;

additionally laying two layers of steel-plastic composite grids 4 on the sand cushion layer, backfilling hard soil 5 on each layer of steel-plastic composite grid 4, and compacting by layered vibration by using a vibration road roller, wherein the compacted thickness is not less than 30cm, and the compaction degree is not less than 90%; the longitudinal stress direction of the installed and laid steel-plastic composite grating 4 is vertical to the axis direction of the road, and the laying requirement is flat, without crease and tensioning; connecting two adjacent steel-plastic composite grating lap joints 4 which are not less than 30cm, binding the two adjacent steel-plastic composite grating lap joints by high-strength nylon ropes every 0.8-1.5 m along the longitudinal direction of a road, and fixing the two adjacent steel-plastic composite grating lap joints on a soil layer by U-shaped nails;

sixthly, after the steel-plastic composite grating 4 is laid and positioned, filling soil in time for covering, wherein the exposure time is not more than 48 hours, adopting a line production method of paving and backfilling at the same time, specifically, paving filler at two sides, fixing the steel-plastic composite grating 4, then pushing the steel-plastic composite grating to the middle, wherein the rolling sequence is that the two sides are paved at first and then the middle is arranged at first, the maximum thickness between the steel-plastic composite grating 4 and a construction machine wheel is not less than 15 cm, and the compaction degree is not less than 95%.

Fifthly, filling requirements of hard soil 5 backfilling between the two middle steel-plastic composite grids 4 are as follows: the internal friction angle is not less than 30 degrees, the plasticity index is not more than 20, and hard and sharp stones cannot be doped to avoid damaging the steel-plastic composite grating.

The depth of the thick and soft soil layer is not more than 4 meters.

The tensile yield force required by each linear meter of the steel-plastic composite grating 4 is as follows: the cross section direction is more than or equal to 100KN/m, and the other direction is more than or equal to 80 KN/m; the yield elongation is less than or equal to 3 percent.

The backfill thickness of the rubble layer 1 is 80-150 cm, and the rubble layer is compacted by vibration of a vibration road roller, wherein the compaction thickness is 30-50 cm, and the compaction degree is not less than 93%.

The backfill thickness of the crushed stone layer 2 is 20-60 cm, and the crushed stone layer is compacted by vibration of a vibration road roller, wherein the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

The backfill thickness of the sand cushion layer 3 is 30-90 cm, and the sand cushion layer is compacted by vibration of a vibration road roller, wherein the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

In the process of excavating thick and soft soil layers of a newly filled soil subgrade, side slopes 6 with different gradients are formed on two sides of the subgrade, the filled soil is in a loose state and is easy to collapse to cause instability of the side slopes 6, and slope placing or sand bag piling measures are adopted during construction to ensure safety of adjacent buildings and construction.

In the fifth step and the sixth step, in order to prevent the vehicle from being damaged by the construction vehicle, the uncompacted steel-plastic composite grating 4 cannot allow the vehicle to run on the grating.

The steel-plastic composite grating 4 is adopted in the scheme of the application, and is a reinforced material, so that the steel-plastic composite grating has six basic functions of reinforcement, isolation, protection, seepage prevention, filtration and drainage. The steel-plastic composite grating 4 is used for treating the bad soil subgrade, the vertical deformation of the upper filler is diffused to the horizontal direction through the steel-plastic composite grating 4, so that the shearing resistance and deformation capacity of the upper filler can be fully exerted, the bearing capacity of the surface of the bad soil subgrade is greatly increased, the surface pressure is correspondingly reduced, and the purpose of improving the bearing capacity of the bad soil subgrade is achieved. Meanwhile, the steel-plastic composite grids 4 are connected vertically and horizontally, so that local sinking of the filler can be prevented, and uneven settlement of the roadbed can be reduced to the greatest extent.

Application example:

in road engineering such as yibin road in Nanning city, Guiya road in Nanning city and the like, the roadbed is the newly filled soil, and the problems of roadbed strength, deformation, uneven settlement and the like occur, so that measures need to be taken to treat the roadbed.

The steps of the scheme are adopted for processing:

firstly, excavating a soft soil layer with the thickness of 4 meters of a newly filled soil subgrade, compacting by using a small-sized vibrator, and detecting the bearing capacity of the subgrade;

secondly, backfilling rubbles after the detection is qualified to form a rubble layer, and applying broken stones for gap filling after backfilling the rubbles;

thirdly, paving a crushed stone layer after rolling compaction;

fourthly, after the gravel layer is paved, medium coarse sand is filled into the gravel layer to form a sand cushion layer;

additionally paving two layers of steel-plastic composite grids on the sand cushion layer, backfilling hard soil on each layer of steel-plastic composite grid, and using a vibration road roller to carry out layered vibration compaction, wherein the compaction thickness is not less than 30cm, and the compaction degree is not less than 90%; the longitudinal stress direction of the installed and laid steel-plastic composite grating is vertical to the axis direction of the road, and the laying requirement is flat, and no crease and tension exist; overlapping two adjacent steel-plastic composite gratings by not less than 30cm, binding the two adjacent steel-plastic composite gratings by high-strength nylon ropes every 0.8-1.5 m along the longitudinal direction of a road, and fixing the two adjacent steel-plastic composite gratings on a soil layer by U-shaped nails;

and finally, after the steel-plastic composite grating is laid and positioned, filling soil in time for covering, wherein the exposure time is not more than 48 hours, a flow process method of paving and backfilling is adopted, specifically, the filling material is paved on two sides firstly, the grating is fixed, then the grating is pushed to the middle part, the rolling sequence is that the two sides are arranged first and then the middle is arranged, the maximum thickness between the steel-plastic composite grating and the wheels of the construction machine is not less than 15 cm, and the compaction degree is not less than 95%.

And in the fifth step, the filling requirement of hard soil backfilling between the two steel-plastic composite grids is as follows: the internal friction angle is not less than 30 degrees, the plasticity index is not more than 20, and hard and sharp stones cannot be doped to avoid damaging the steel-plastic composite grating.

Wherein, the tensile yield force required by each linear meter of the steel-plastic composite grating is as follows: the cross section direction is more than or equal to 100KN/m, and the other direction is more than or equal to 80 KN/m; the yield elongation is less than or equal to 3 percent.

Wherein the backfill thickness of the rubble layer is 100cm, the rubble layer is tightly vibrated by a vibration road roller, the compaction thickness is 30-50 cm, and the compaction degree is not less than 93%.

Wherein the backfill thickness of the crushed stone layer is 30cm, the crushed stone layer is compacted by vibration of a vibration road roller, the compaction thickness is 15-18 cm, and the compaction degree is not less than 93%.

The backfilling thickness of the sand cushion layer is 50cm, the sand cushion layer is tightly vibrated by a vibration road roller, the compacting thickness is 15-18 cm, and the compacting degree is not less than 93%.

Wherein, the construction adopts the sand bag to pile up the means to guarantee the safety of neighbouring building and construction.

Wherein, the marker is arranged above the uncompacted steel-plastic composite grating, so that the vehicle cannot run on the marker.

By the treatment of the scheme, the roadbed strength is improved, the roadbed stability is guaranteed, the uneven settlement is prevented, the excavation range is small, the construction is convenient, the investment is saved, and the stability problem of a recent road bed filling is effectively solved. At present, the road has been completed for many years and has good effect.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.