CN111188234A

CN111188234A - Method for enhancing construction quality of red sandstone roadbed

Info

Publication number: CN111188234A
Application number: CN202010027204.XA
Authority: CN
Inventors: 赵亚杰; 喻其风; 王勇
Original assignee: China MCC17 Group Co Ltd
Current assignee: China MCC17 Group Co Ltd
Priority date: 2020-01-10
Filing date: 2020-01-10
Publication date: 2020-05-22

Abstract

The invention relates to a method for enhancing construction quality of a red sandstone roadbed, which belongs to a construction method of roads and is characterized in that: the construction quality of the red sandstone roadbed is enhanced by controlling the procedures of raw material treatment, material proportion, water content, virtual paving thickness, construction machinery, geotechnical materials and the like of the red sandstone backfill, and the construction process of the method for enhancing the construction quality of the red sandstone roadbed comprises the following steps: the red sandstone pre-disintegration → layered paving, scarifying, rolling, red sandstone re-disintegration → red sand soil improvement → layered paving of roadbed, rolling → setting of geotechnical material → setting of roadbed top water-resisting layer → acceptance inspection, the process is simple and practical, the raw materials of the construction site are fully utilized, a large amount of abandonment and borrowing filling are avoided, the construction cost is reduced, the engineering progress is accelerated, and the construction quality of the roadbed in the red sandstone area is improved.

Description

Method for enhancing construction quality of red sandstone roadbed

Technical Field

The invention belongs to a road construction method, and particularly relates to a method for enhancing the construction quality of a roadbed.

Background

The road construction of China develops rapidly, in the road construction process, without a high-quality roadbed foundation, the high-quality road construction is difficult to guarantee, the roadbed is usually the most potential procedure of the accident potential of the road quality, the subsequent construction such as pavement engineering, protection engineering and the like can build a high-quality road depending on the high quality of the roadbed, the roadbed engineering is the most important link in the road construction, so in the road construction process, special attention should be given, and a series of scientific measures are adopted to guarantee the construction quality of the roadbed.

The red sandstone is a common rock mass, is cemented in a argillaceous manner, is red, brownish red and the like due to oxides rich in iron, is collectively called as red sandstone, is in a sand grain structure, is cemented in a argillaceous manner, is gradually disintegrated under the action of atmosphere, sunlight and particularly rainwater after being excavated, and has the characteristics of low strength, small softening coefficient and activity after disintegration, so that the red sandstone is used as road building filler in road construction, has high construction difficulty, and often causes the problems of subgrade collapse and pavement cracking.

Disclosure of Invention

The invention aims to provide a method for enhancing the construction quality of a red sandstone roadbed, which aims at overcoming the defects of the prior art, solves the problems that the red sandstone is easy to cause roadbed subsidence and pavement cracking when being used as a road filling material, and improves the construction quality of the roadbed.

The purpose of the invention is realized by the following steps: a method for enhancing construction quality of a red sandstone roadbed is characterized by comprising the following steps: the construction quality of the red sandstone roadbed is enhanced by controlling the procedures of raw material treatment, material proportion, water content, virtual paving thickness, construction machinery, geotechnical materials and the like of the red sandstone backfill, and the construction process of the method for enhancing the construction quality of the red sandstone roadbed comprises the following steps: pre-disintegration of red sandstone (i.e. one treatment of raw materials) → layered paving, scarification, rolling, re-disintegration of red sandstone (i.e. two treatment of raw materials) → redsand soil improvement (i.e. three treatment of raw materials) → layered paving of roadbed, rolling → arrangement of geotechnical materials → arrangement of water-proof layer on top of roadbed → acceptance. Wherein:

first), pre-disintegration of red sandstone (i.e., one of the treatments of raw materials):

the red sandstone is subjected to pre-disintegration treatment, the excavated red sandstone or an in-situ or an additionally arranged treatment site is rapidly weathered and disintegrated under the action of natural factors such as atmosphere, sunlight, rainwater and the like, the strength of the red sandstone is rapidly reduced, the activity of the red sandstone is rapidly eliminated, watering is carried out on a sunny day according to the temperature condition during the pre-disintegration period, when the temperature is 38-24 ℃, watering can be carried out once every morning and evening, and a shovel is used for turning and stirring for 1 time at noon and 4-6 days to convert large blocks of red sandstone into red sand soil containing small blocks of red sandstone, so that the red sandstone is disintegrated and softened into the red sand soil, and the disintegration of the red sand soil is eliminated.

Second), paving, raking, rolling, reduplicating the red sandstone (namely, the second treatment of the raw materials):

the redsand stone re-disintegration is to pave the redsand stone (soil) after pre-disintegration treatment in a backfill-planned area of a roadbed, wherein the paving thickness is 150mm-160mm, the red sand stone pile is pushed to be flat by using a general bulldozer, the red sand stone pile is rolled by a crawler, then a rotary cultivator is used for harrowing, and mist water is sprayed to accelerate the reduction of the activity of the redsand stone, after airing, the red sand stone is continuously rolled by using a general claw roller and the rotary cultivator is harrowed to be loose, and the red sand stone is circularly operated for 2-4 times after the rotary cultivator is harrowed loose → water spraying disintegration → claw roller rolling, and when the temperature is 38-24 ℃ in summer, one operation cycle is as follows: raking and loosening for 1 time by using a common agricultural rotary cultivator, spraying mist water by using a high-pressure water gun of a water spraying truck to ensure that the surface of the soil is moist but no water is accumulated, airing until the surface of the soil is dry, and then performing next circulation to ensure that the red sandstone becomes the red sand.

Thirdly), red sandy soil improvement (namely, the third treatment of raw materials):

improve the red sandy soil after disintegration treatment by using loess and slaked lime, and according to the weight ratio, the red sandy soil is prepared by the following steps: loess: slaked lime (slaked lime) 75: 20: and 5, during construction, directly adding loess and hydrated lime into the red sandy soil subjected to disintegration treatment in proportion, stirring by using a universal lime-soil stirring machine, controlling the water content to be 9-11%, and keeping the water content so as to accelerate the active degradation of the red sandy soil in the backfill.

Fourthly), layered paving and rolling of the roadbed:

the red sandy soil after disintegration treatment and improvement is used as a roadbed filler, the virtual paving thickness of each layer of filler is not more than 200mm during construction, the filler is mixed by a general lime-soil mixing machine for 3-5 times, then a general crawler machine is used for preliminary pressing and leveling by a leveler, then a general goat horn roller is used for rolling, the compactness meets the design requirement, after the experience is closed, the next layer of red sandy soil is backfilled, and finally the last layer of red sandy soil is rolled by a general smooth-wheel roller.

Fifthly), setting of the geotechnical material:

in the filling area of the roadbed, red sand is 1m high after being backfilled, an outsourced geogrid is used for paving the roadbed once in a full width mode, the length of a reverse turning bag at the periphery of the geogrid is not less than 1.5m, (see figure 1), after the red sand filling construction of the roadbed is finished, the top surface of the red sand roadbed is covered in the full width mode by outsourced waterproof geotextile, and the covering surfaces at the four peripheries of the waterproof geotextile extend downwards for 1.50m-2.0m along the top inclined surface of the roadbed to play a water-proof role (see figure 2).

Six), setting up of road bed top water barrier:

more than the red sandstone roadbed roof (more than the upper surface of waterproof geotechnical cloth) height (thickness) of the red sandy soil backfill area of the roadbed is a lime soil layer (namely a stirring layer of loess and hydrated lime) within 40cm, a 6% lime soil layer is used as a water barrier on the upper surface of the waterproof geotechnical cloth, 6% lime soil is hydrated lime weight/total lime soil weight, the water barrier is backfilled and rolled in two layers, the thickness of each layer is 20cm, and a general smooth-wheel road roller is used, so that the compactness meets the design rolling requirement.

The method for enhancing the construction quality of the red sandstone roadbed provided by the invention solves the problems that the red sandstone is easy to cause roadbed subsidence and pavement cracking when being used as a road filling material aiming at the defects of the prior art, and improves the construction quality of the roadbed.

The method for enhancing the construction quality of the red sandstone roadbed provided by the invention is further explained by combining the attached drawings and the embodiment.

Drawings

Fig. 1 is a schematic view illustrating the arrangement of geogrids in the method for enhancing the construction quality of the red sandstone roadbed according to the invention.

Fig. 2 is a schematic view of the arrangement of the waterproof geotextile in the method for enhancing the construction quality of the red sandstone roadbed.

Fig. 3 is a schematic diagram of the arrangement of the roadbed top water-resisting layer in the method for enhancing the construction quality of the red sandstone roadbed.

Fig. 4 is an enlarged schematic view of a in fig. 1.

Fig. 5 is an enlarged schematic view of B in fig. 2.

In fig. 1, 2, 3, 4, and 5:

1. roadbed 2, geogrid 3, waterproof geotextile 4 and water-proof layer

Examples

In the construction of the road engineering of the Huanning municipal project, the method for enhancing the construction quality of the red sandstone roadbed is adopted for the roadbed construction of the red sandstone area.

Firstly, carrying out test section construction: the construction method comprises the steps of carrying out 20-40m test section construction in a test field (an informal road), recording data such as construction sequence, rolling machine, rolling times, raking and pressing times and the like, regularly observing and detecting phenomena such as settlement, cracks and the like after the test construction is finished, recording in detail, carrying out experiments such as load, damage and the like if necessary, detecting the construction quality of the test section, and obtaining the experience of red sandstone roadbed construction.

Then, the construction process provided by the invention is adopted for roadbed construction of the red sandstone area in the road engineering of the Huanning municipal project:

the red sandstone is subjected to pre-disintegration treatment, the excavated red sandstone or an in-situ or additionally arranged treatment site is rapidly weathered and disintegrated under the action of natural factors such as atmosphere, sunlight, rainwater and the like, the strength of the red sandstone is rapidly reduced, the activity of the red sandstone is rapidly eliminated, during the pre-disintegration, the red sandstone is watered according to the temperature condition on a sunny day, the red sandstone is promoted to disintegrate and soften into red sand, the disintegration is eliminated, in the summer of the Huanning area, the highest temperature is 38 ℃, the lowest temperature is 24 ℃, the red sand is watered once in the morning and evening every day, the red sand is stirred by a digger for 1 time at noon, and a large block of red sandstone is converted into the red sand containing a small block of red sandstone in 4 days.

Secondly), paving, harrowing, rolling and redbreak of the red sandstone:

the redsand rock re-disintegration is to pave the redsand rock (soil) after pre-disintegration treatment around the backfill-planned area of the roadbed, the paving thickness is 150mm, the heaps of the redsand rock are pushed flat by using a general bulldozer, the redsand rock is rolled by a crawler, then a rotary cultivator is used for harrowing, and mist water is sprayed to accelerate the reduction of the activity of the redsand rock, after airing, the redsand rock is continuously rolled by using a general goat horn roller and harrowed by a general bulldozer, the redsand rock is rolled by a rotary cultivator → water sprinkling disintegration → goat horn roller, the operation is circulated for 4 times, the redsand rock becomes redsand soil, and in summer in the area of Huanning, one operation cycle is as follows: raking and loosening for 1 time by using a common agricultural rotary cultivator, spraying mist water by using a high-pressure water gun of a water spraying truck to ensure that the surface of the soil is wet but no water is accumulated, airing until the surface of the soil is dry, and then performing the next operation and circulating in sequence.

Thirdly), mixing lime soil and improving red sand soil:

improve the red sandy soil after disintegration treatment by using loess and slaked lime, and according to the weight ratio, the red sandy soil is prepared by the following steps: loess: hydrated lime 75: 20: and 5, during construction, directly adding loess and hydrated lime into the red sandy soil subjected to the disintegration treatment according to the proportion, and stirring by using a general lime-soil stirring machine, wherein the water content is controlled to be 9-11% so as to accelerate the active degradation of the red sandy soil in the backfill material.

Fourthly), layered paving and rolling of the roadbed:

the red sandy soil after disintegration treatment and improvement is used as the filler of the roadbed 1, the virtual paving thickness of each layer of filler is not more than 200mm during construction, the filler is mixed for 5 times by a general lime-soil mixing machine, then the filler is primarily pressed by a general crawler machine and leveled by a leveler, then the filler is rolled by a general goat horn roller, the compactness meets the design requirement, the red sandy soil of the next layer is backfilled after the experience is closed, and the red sandy soil of the last layer is rolled by a general smooth-wheel roller.

Fifthly), setting of the geotechnical material:

in the filling area of the roadbed 1, red sandy soil is filled to 1m height every time, the outsourced geogrid 2 is used for paving once in a whole width, the length of a reverse turning bag at the periphery of the geogrid 2 is 1.5m, (see figure 1), after the red sandy soil filling construction of the roadbed 1 is finished, the whole width of the top surface of the roadbed 1 is covered by outsourced waterproof geotextile 3, and the covering surface of the periphery of the waterproof geotextile 3 extends downwards for 1.5m along the top inclined plane of the roadbed 1 to play a role of water insulation (see figure 2).

Six), setting up of road bed top water barrier:

in the height range of 40cm above the top of a red sandy soil backfilling area of a roadbed 1, 6% of lime soil layers (namely stirring layers of loess and hydrated lime) are used as a waterproof layer 4 on the upper surface of a waterproof geotextile 3, the 6% of lime soil is the weight of the hydrated lime/the weight of the total lime soil, the waterproof layer 4 is backfilled and rolled in two layers, each layer is 20cm thick, and a general smooth-wheel roller is used for rolling, so that the compactness meets the design requirement.

In the construction of the road engineering of the Huanning municipal project, the method for enhancing the construction quality of the red sandstone roadbed is simple to implement, the raw materials on site are fully utilized, a large number of abandonments and borrow filling are avoided, the segmented line production is carried out, the disintegration treatment hardly occupies extra construction period, the construction cost is reduced, the engineering progress is accelerated, and the construction quality of the roadbed in the red sandstone area is improved.

Claims

1. A method for enhancing construction quality of a red sandstone roadbed is characterized by comprising the following steps: the construction quality of the red sandstone roadbed is enhanced by controlling the procedures of raw material treatment, material proportion, water content, virtual paving thickness, construction machinery, geotechnical materials and the like of the red sandstone backfill;

the construction process of the method for enhancing the construction quality of the red sandstone roadbed comprises the following steps: pre-disintegration of red sandstone → layered paving, harrowing, rolling, re-disintegration of red sandstone → improvement of red sand soil → layered paving of roadbed, rolling → arrangement of geotechnical material → arrangement of water-resisting layer on top of roadbed → acceptance;

wherein:

first), pre-disintegration of red sandstone:

the red sandstone is subjected to pre-disintegration treatment, the excavated red sandstone or an in-situ or an additionally arranged treatment site is rapidly weathered and disintegrated under the action of natural factors such as atmosphere, sunlight, rainwater and the like, the strength of the red sandstone is rapidly reduced, the activity of the red sandstone is rapidly eliminated, watering is carried out on a sunny day according to the temperature condition during the pre-disintegration, when the temperature is 38-24 ℃, watering can be carried out once every morning and evening, and a shovel is used for turning and stirring for 1 time at noon and 4-6 days to convert a large block of red sandstone into red sandy soil containing a small block of red sandstone, so that the red sandstone is disintegrated and softened into the red sandy soil and the disintegration of the red sandy soil is eliminated;

secondly), layered paving, harrowing, rolling and redbreak of the red sandstone:

the redsand rock re-disintegration is to spread the redsand rock after pre-disintegration treatment in a backfill-proposed area of a roadbed, wherein the spreading thickness is 150mm-160mm, the red sand rock pile is pushed to be flat by using a general bulldozer, rolled by a crawler, raked by a rotary cultivator, and sprayed with mist water to accelerate the reduction of the activity of the redsand rock, after airing, the redsand rock is continuously rolled by using a general claw roller and raked by the rotary cultivator, and is circularly operated for 2-4 times after the raked by the rotary cultivator → sprinkled water disintegration → claw roller, and when the temperature is 38-24 ℃ in summer, the operation cycle is as follows: raking for 1 time by using a common agricultural rotary cultivator, spraying mist water by using a high-pressure water gun of a water spraying truck to wet the surface of the soil material but not accumulate water, airing until the surface of the soil material is dry, and performing next operation cycle to make the red sandstone into red sand;

thirdly), improving the red sandy soil:

improve the red sandy soil after disintegration treatment by using loess and slaked lime, and according to the weight ratio, the red sandy soil is prepared by the following steps: loess: slaked lime, i.e. slaked lime after digestion, 75: 20: 5, during construction, directly adding loess and hydrated lime into the red sandy soil subjected to disintegration treatment according to the proportion, stirring by using a general lime-soil mixer, controlling the water content to be 9-11%, and keeping the water content to accelerate the active degradation of the red sandy soil in the backfill;

fourthly), layered paving and rolling of the roadbed:

the red sandy soil after disintegration treatment and improvement is used as a filler of a roadbed (1), during construction, the virtual paving thickness of each layer of filler is not more than 200mm, the filler is mixed for 3-5 times by a universal lime-soil mixing machine, then the filler is primarily pressed by a universal crawler machine and leveled by a leveler, then the filler is rolled by a universal goat-horn roller, so that the compactness meets the design requirement, after the empirical folding lattice, the next layer of red sandy soil is backfilled, and finally the red sandy soil layer is rolled by a universal smooth-wheel roller;

fifthly), setting of the geotechnical material:

in a filling area of a roadbed (1), red sandy soil is backfilled for 1m high, an outsourced geogrid (2) is used for paving once in a full width mode, the length of a reverse turning bag at the periphery of the geogrid (2) is not less than 1.5m, after the red sandy soil filling construction of the roadbed (1) is finished, the top surface of the roadbed (1) is covered by outsourced waterproof geotextile (3) in a full width mode, and the covering surfaces at the four peripheries of the waterproof geotextile (3) extend downwards for 1.5-2.0m along the top inclined plane of the roadbed (1) to play a role of water insulation;

six), setting up of road bed top water barrier:

the height above the red sandstone roadbed roof of the red sand soil backfilling area of the roadbed (1), namely the height above the upper surface of the waterproof geotextile (3), namely the thickness is within 40cm, is a lime soil layer, namely a stirring layer of loess and hydrated lime, 6% of the lime soil layer is used as a water-resisting layer (4) on the upper surface of the waterproof geotextile (3), 6% of the lime soil is hydrated lime weight/total lime soil weight, the water-resisting layer (4) is backfilled and rolled in two layers, the thickness of each layer is 20cm, a universal smooth-wheel road roller is used for rolling, and the degree of compaction meets the design requirement.