CN203403426U - Supporting structure of expensive earth road cutting side slope - Google Patents

Abstract

The utility model relates to an expansive soil cutting slope support structure, in particular to the protection field of road and railway cutting slopes in expansive soil areas. It includes three parts: rigid support system, flexible protection system and waterproof and drainage system. The rigid support system is that it includes lame retaining wall and retaining wall foundation arranged on expansive soil cutting slope; the flexible support system includes setting on Sash beams, anchor rods, flexible mesh geogrids laid on the slope and vegetation planted on the slope on the expansive soil cutting slope; Or drainage ditches, pervious layers behind retaining walls, drainage ditches and drainage ditches under gutters. The slope is protected by a flexible support system. Compared with the rigid support method of the slope full-paved grouted stone structure, the project cost is more than 20% lower, and the construction period is much shorter; expansion force.

Description

Expansive Soil Cutting Slope Support Structure

technical field

The utility model relates to an expansive soil cutting slope support structure, in particular to the protection field of road and railway cutting slopes in expansive soil areas.

Background technique

Expansive soil is mainly composed of strongly hydrophilic clay minerals montmorillonite and illite. It is a highly plastic cohesive soil with expansive structure, multiple cracks, strong expansion and contraction, and strength attenuation. It is also a typical unsaturated soil. . It is widely distributed in the world, and it is mainly distributed in more than 20 provinces and autonomous regions such as Hubei, Shaanxi, Yunnan, Guangxi, and Henan in my country, and it is mainly formed by residual deposits or residual slope deposits. Expansive soil brings harm to human engineering activities, and its strength attenuation characteristics caused by repeated expansion and contraction deformation due to water absorption and loss of water have long-term potential damage to engineering facilities. The situation that my country's highways and railways are endangered by it is very serious. There is a saying that "every cut will collapse, and no embankment will not collapse" on highways and railways passing through expansive soil. Since the 1990s, my country has begun to build high-grade highways on a large scale. The newly built highways pass through expansive soil areas. The lateral unloading effect of road cutting excavation causes the soil to expand and deform toward the excavation surface. Shallow collapse damage caused by water cracking is very common. Improper treatment of expansive soil embankment filling and structure foundation will pose a serious threat to the safety of the project. Therefore, the stability and protection of expansive soil cutting slopes have become thorny and unavoidable problems in engineering practice.

Through literature search, there are many structures and forms used to deal with expansive soil slopes, such as replacement of filling soil, improvement of expansive soil, slope protection with full mortar masonry rubble, retaining wall at the slope foot, greening slope after slowing slope ratio, adding Reinforced soil slope protection, rainwater seepage prevention and other measures and methods, but according to the actual situation of the project, it is found that the replacement of filling soil or improved soil will increase the project cost, and the construction period will be longer; Moreover, after a period of use, there will be arching and cracking of the slope flakes, and the slope will collapse after a long time; the retaining wall structure at the foot of the slope alone cannot effectively deal with the expansive soil slope, and the cost of the reinforced earth retaining wall for slope protection is too high. Some of the above-mentioned treatment methods are not processed according to the failure mechanism of expansive soil slopes, the characteristics of landslides and the engineering characteristics of expansive soils, or the cost of the treatment methods is too high and the construction period is too long. Therefore, it is a big problem for technicians to find a protective method that not only considers the engineering characteristics of expansive soil, but also is economical and environmentally friendly.

Utility model content

In order to overcome the above-mentioned defects, the purpose of this utility model is to provide an expansive soil cutting slope support with simple structure, convenient on-site construction, low engineering cost, green environmental protection, and conforming to the engineering characteristics of expansive soil. structure and its method of construction.

In order to achieve the above object, the utility model adopts the following technical solutions:

An expansive soil cutting slope support structure, which includes three parts: a rigid support system, a flexible protection system and a waterproof and drainage system:

The rigid support system is that it includes a lame retaining wall and a retaining wall foundation arranged on the expansive soil cutting slope;

The flexible support system includes frame beams arranged on the expansive soil cutting slope, anchor rods, flexible mesh geogrid laid on the slope, and vegetation planted on the slope;

The waterproof and drainage system includes intercepting ditch or drainage ditch arranged on the slope top, permeable layer behind the retaining wall, drainage ditch and drainage seepage ditch under the drainage ditch.

The base elevation of the above-mentioned retaining wall must exceed the atmospheric influence depth of expansive soil by more than 0.5m in the area, and the natural bearing capacity of the base must be greater than 200kpa. The retaining wall is made of flake concrete, and the strength of the concrete must not be less than C20.

The anchoring depth of the anchor rod must exceed the atmospheric influence depth of the expansive soil in the area by more than 1m, and the diameter of the anchor rod is a threaded steel bar not less than 16mm.

The distance between nodes of the sash beams is 2.5-3.5m, the sash beams are made of reinforced concrete, and the strength of the concrete is C20.

The flexible mesh geogrid adopts a bidirectional geogrid with a grid size of 20cm*20cm or 30cm*30cm, and each piece of geogrid is connected and fixed by a U-shaped slot to connect all geogrids into a whole. Make it together with the sash anchor beam to form a flexible support structure.

A layer of waterproof geotextile I is laid on the bottom of the intercepting ditch or drainage ditch.

The top of the retaining wall is provided with an inverted trapezoidal groove. The groove size is 30-40cm deep, 40-50cm wide at the top, and 30-40cm wide at the bottom. Backfill the planting soil in the groove, and plant jasmine shrubs. To the purpose of the retaining wall at the foot of the green slope.

A drain pipe is buried deep in the retaining wall, the end of the drain pipe near the retaining wall is wrapped with a water-permeable geotextile, and the other end of the drain pipe is connected to a drainage seepage ditch.

In the drainage seepage ditch, waterproof geotextile III is laid on the surface of the expansive soil body, and a soft drainage pipe is buried in the middle of the drainage seepage ditch, and the soft drainage pipe is wrapped with a permeable geotextile.

A construction method of expansive soil cutting slope support structure:

(1) Excavate the expansive soil cutting according to the slope ratio, and reserve 30-50cm for the thickness of backfilling planting soil;

(2) Determine the atmospheric influence depth of expansive soil according to the local expansive soil regional building technical specifications;

(3) Excavate the base elevation of the retaining wall to a position at least 1m above the atmospheric influence depth of the expansive soil, lay a layer of waterproof geotextile II on the excavation surface of the slope behind the wall, and then pour concrete for the retaining wall;

(4) When pouring the concrete of the retaining wall, a drain pipe must be buried in the retaining wall. The drain pipe is made of PVC pipe with a slope of 3%. After removing the formwork, backfill the wall with permeable gravel 20-30cm and compact it;

(5) Excavate the beam groove on the slope according to the distance between the frame beam nodes of 2.5-3.5m. The size of the beam groove is a rectangular section with a width of 20cm and a depth of 30cm. After the beam groove is excavated, lay a flexible mesh geogrid , and then place the reinforcement cage and pour the concrete. Before pouring the concrete, the anchor holes must be reserved at the joints of the sash beams;

(6) When the concrete of the sash beam reaches the design strength, drill a hole vertically at the reserved anchor hole. The depth of the hole must be more than 1m greater than the atmospheric influence depth of the expansive soil. Then pour cement mortar into the hole and insert the anchor In the hole, fix the anchor plate and nut at the end of the anchor rod, and then pour concrete to seal the anchor head;

(7) Excavate the intercepting ditch or drainage ditch at the top of the slope to the design elevation, then lay a layer of waterproof geotextile I, and build the intercepting ditch or drainage ditch on the waterproof geotextile I;

(8) Backfill the slope with 30-50cm thick planting soil, and plant vegetation on the planting soil: grass, shrubs and trees.

Set up a gravity retaining wall at the foot of the slope (the base elevation of the retaining wall must be set at 0.5m above the atmospheric influence depth of the expansive soil), as a rigid support mainly to prevent the expansive soil from sliding from the foot of the slope, and to the direction of the top of the slope by traction Development; set up diamond-shaped frame beams and a layer of mesh geogrid on the slope, and use anchors to fix them on the slope (the anchor must be anchored to a depth of at least 1m above the atmospheric influence of expansive soil), and then backfill the planting soil , planting vegetation suitable for the growth of the area, forming a flexible support system, which allows the slope to deform, eliminates the swelling force generated when the expansive soil meets water, and achieves the effect of controlling rigidity with flexibility. Comprehensive waterproof and drainage devices are installed on the top of the slope, the back of the retaining wall, and the side ditch of the road cutting, which can timely drain away the rainwater on the slope and the stagnant water in the slope, and add the functions of evaporation, water retention and anti-scouring of the vegetation on the slope, so that the The water content of the slope expansive soil is kept in a relatively balanced state to maintain the long-term stability of the slope.

working principle:

1. Rigid support system. It is mainly composed of a retaining wall. The retaining wall adopts a gravity retaining wall. The width of the top of the wall is 50-80cm. 200kpa, the wall material is flake concrete, and the concrete strength is C20. Backfill the gravel permeable layer behind the wall. The thickness of the gravel permeable layer is 20-30cm. The backfill depth of the gravel permeable layer should not be lower than the atmospheric influence depth of expansive soil. A layer of waterproof geotextile is laid on the slope, and PVC drainage pipes must be buried every 1-1.5m on the retaining wall to remove the stagnant water in the permeable layer of gravel on the retaining wall.

2. Flexible support system. The flexible support system is mainly composed of frame beams, anchor rods, mesh geogrids, and slope vegetation. Firstly, excavate the expansive soil slope according to the slope ratio of 1:1.75-1:2. Note that the brush slope should be 50cm longer than the design, because the planting soil should be reserved. Then excavate the diamond-shaped frame beam slots according to the design requirements. The distance between the diamond-shaped frame beams can be 2.5-3.5m. The size of the grid beams is 30cm deep and 20cm wide. The diameter is 12-14cm, the steel bar spacing is 10-15cm, and the steel bar connection can be tied with iron wire. After the grid groove is excavated, a layer of mesh geogrid is laid along the entire slope with a mesh geogrid network, and it is also laid in the grid groove. The geogrid is connected with a U-shaped buckle, and the geogrid The grid can adopt a two-way geogrid with a mesh size of 20-30cm. When pouring lattice beam concrete, anchor holes must be reserved at the joints of the lattice beams. PVC pipes with a diameter of 5cm can be used, and the PVC pipes should be pre-buried vertically on the slope. The anchor rod adopts threaded steel bars with a diameter of 16cm. The length of the anchor rod must be greater than the atmospheric influence depth of expansive soil by more than 1m. After the hole is formed, cement mortar is injected into the anchor hole, and then the anchor is inserted into the hole, which can prevent the anchor from rusting. Set the anchor plate at the joint of the lattice beam, tighten and fix the anchor rod with steel nuts, and then pour the anchor head with concrete to prevent corrosion. After the construction of the sash beams and anchor rods, lay a layer of planting soil (non-expansive soil) on the slope, sow grass seeds suitable for the area in the planting soil, and plant shrubs suitable for the area after the planting grass survives. After the shrubs survive, plant trees suitable for the area. In this way, herbaceous plants (root system can reach 20-30cm) can prevent rain from washing the slope, shrubs (root system can reach 60-70cm) and trees (root system can reach 100- 150cm or more) The well-developed root system can fix the slope, reduce the evaporation of water in the slope, maintain the water balance in the slope, effectively protect the slope, and green the slope to beautify the road.

3. Waterproof and drainage system. The waterproof and drainage system is mainly composed of drainage ditch at the top of slope, drainage behind retaining wall, side ditch of road cutting and drainage of seepage ditch. The drainage ditch at the top of the slope is mainly to intercept and drain the natural rainwater on the top of the slope, so as to prevent the rainwater from scouring the slope and penetrating into the slope body. After the drainage ditch is excavated at the top of the slope, a layer of waterproof geotextile should be laid on the bottom of the ditch in time to prevent rainwater from penetrating into the slope, and then a drainage ditch should be constructed on the geotextile. The drainage behind the retaining wall is mainly to remove the rainwater flowing down the slope and the seepage water in the slope. When the retaining wall is excavated to the design position, waterproof geotextiles should be laid on the slope behind the wall in time to prevent the accumulated water flowing down from the slope from seeping into the slope. Permeable materials such as crushed stone or gravel can be used for the drainage layer behind the retaining wall. At a certain depth of the retaining wall (the depth affected by the atmosphere of expansive soil in this area), drain pipes must be buried at certain distances. The drain pipes can be pre-embedded with PVC materials when the retaining wall is poured with concrete. slope for drainage. The end of the drain pipe against the retaining wall needs to be wrapped with a permeable geotextile to prevent the soil from blocking the pipe, and the other end of the drain pipe is connected to the drainage ditch under the side ditch. The side ditch of the cutting is mainly to remove the rainwater on the road surface and part of the surface water within the cutting range, and the seepage ditch under the side ditch is mainly to remove the accumulated water behind the retaining wall, the accumulated water in the slope body and the accumulated water in the roadbed, etc. After the seepage ditch is excavated according to the design, the waterproof geotextile must be laid on the surface of the excavated expansive soil, and then the seepage ditch shall be constructed on the waterproof geotextile, and the drainage ditch shall be built after the construction of the seepage ditch is completed. It is suggested that the road bed of the cutting should be replaced with soil with better physical properties (or improved expansive soil), and then paved with waterproof geotextiles together with the expansive soil surface at the bottom of the ditch to achieve the overall waterproof effect.

Compared with the prior art, the utility model has the following advantages:

(1) Considering that the landslide of expansive soil slope mainly starts from the foot of the slope, and then slowly upwards, it is very necessary to set up a retaining wall at the foot of the slope;

(2) The slope surface is protected by a flexible support system. Compared with the rigid support method of the slope surface full of grouted masonry structure, the project cost is more than 20% lower, and the construction period is much shorter;

(3) The flexible support system adopts the combination of grid beam bolts and mesh geogrid. The mesh geogrid allows a certain amount of deformation, which can effectively release the expansion force generated when the expansive soil expands with rainwater, so as to achieve the goal of overcoming rigidity with softness. Purpose;

(4) Due to the relatively large mesh geogrid, various vegetation can be cultivated conveniently. It can not only solidify the slope and maintain soil moisture, but also achieve the purpose of greening the slope and beautifying the road appearance.

Description of drawings

Fig. 1 is a cross-sectional schematic diagram of the utility model;

Fig. 2 is the cross-sectional schematic view of the anchor rod and anchor head at the grid beam joint of the utility model;

Fig. 3 is the schematic plan view of the slope frame beam anchor rod of the present utility model;

Fig. 4 is a schematic cross-sectional view of the top structure of the retaining wall of the present invention.

Among them, 1-retaining wall; 2-frame beam; 3-anchor; 4-flexible mesh geogrid; 5-vegetation; 6-waterproof geotextile Ⅰ; Permeable layer behind the retaining wall; 9-waterproof geotextile II; 10-drainage pipe; 11-waterproof geotextile III; 12-drainage seepage ditch; 13-soft drainage pipe; 14-drainage ditch; Anchor backing plate; 17-bolt hole; 18-drainage pipe.

Detailed ways

Below in conjunction with accompanying drawing 1,2,3,4 the utility model is described in detail:

An expansive soil cutting slope support structure, which includes three parts: a rigid support system, a flexible protection system and a waterproof and drainage system.

The rigid support system is that it includes a lame retaining wall 1 and a retaining wall foundation arranged on the expansive soil cutting slope;

Described flexible support system it comprises the frame beam 2 that is arranged on the expansive soil cutting slope, the anchor rod 3, the flexible mesh geogrid 4 that lays on the slope surface and the vegetation 5 that is planted on the slope surface; First Excavate the expansive soil slope according to the slope ratio of 1:1.75-1:2. Note that the brush slope should be 50cm longer than the design, because the planting soil should be reserved.

The waterproof and drainage system includes an intercepting ditch or drainage ditch 7 arranged on the top of the slope, a permeable layer 8 behind the retaining wall, a drainage ditch 14 and a drainage seepage ditch 12 under the drainage ditch 14 .

Intercepting ditch or drainage ditch 7 are mainly to intercept and get rid of the natural rainwater on the top of the slope, so as to prevent rainwater from scouring the slope surface and infiltrating into the slope body.

The drainage ditch 14 mainly removes rainwater on the road surface and part of the surface water in the cutting range, and the drainage seepage ditch 12 under the side ditch mainly removes the accumulated water behind the retaining wall 1, the accumulated water in the slope body and the accumulated water in the roadbed.

The position of the base elevation of the above-mentioned retaining wall 1 must exceed the atmospheric influence depth of expansive soil in this area by more than 0.5m, and the natural bearing capacity of the base must be greater than 200kpa. The retaining wall 1 is made of rubble concrete, and the strength of the concrete must not be less than C20.

The anchoring depth of the anchor rod 3 must exceed the atmospheric influence depth of the expansive soil in this area by more than 1m, and the diameter of the anchor rod is a threaded steel bar not less than 16mm.

The distance between the nodes of the sash beam 2 is 2.5-3.5m, the sash beam 2 is made of reinforced concrete, and the concrete strength label is C20.

The flexible mesh geogrid 4 adopts a two-way geogrid with a grid size of 20cm*20cm or 30cm*30cm, and each piece of geogrid is connected and fixed by a U-shaped slot to connect all geogrids into a whole , so that it forms a flexible support structure together with the sash anchor beam.

A layer of waterproof geotextile I6 is laid on the bottom of the intercepting ditch or drainage ditch 7 . Prevent rainwater from penetrating into the slope body, and then make intercepting ditch or drainage ditch 7 on the waterproof geotextile I6.

The top of the wall of the retaining wall 1 is provided with an inverted trapezoidal groove, the groove size is 30-40cm deep, 40-50cm wide at the top, and 30-40cm wide at the bottom, backfilling the planting soil in the groove, and planting jasmine shrubs, Play the purpose of greening slope foot retaining wall

The water-permeable layer 8 behind the retaining wall adopts gravel or gravel water-permeable materials. The permeable layer behind the retaining wall is mainly to remove the rainwater flowing down the slope and the seepage water in the slope.

Backfill the gravel permeable layer behind the wall. The thickness of the gravel permeable layer is 20-30cm. The backfill depth of the gravel permeable layer should not be lower than the atmospheric influence depth of expansive soil. Lay a layer of waterproof geotextile II9 on the slope surface to prevent the accumulated water flowing down from the slope surface from seeping into the slope body.

In the depth of the retaining wall 1 , a drain pipe 10 is buried. The end of the drain pipe 10 near the retaining wall 1 is wrapped with a water-permeable geotextile, and the other end of the drain pipe 10 is connected to a drainage ditch 12 . A drainpipe 10 must be buried every 1-1.5m in the retaining wall to remove the stagnant water in the gravel permeable layer of the retaining wall, and the slope of the drainpipe is set at 3%.

In the drainage seepage ditch 12, a waterproof geotextile III11 is laid on the surface of the expansive soil body, and a soft drainage pipe 13 is embedded in the middle of the drainage seepage ditch 12, and the soft drainage pipe 13 is wrapped with a water-permeable geotextile.

The specific implementation steps are as follows:

(1) Excavate the expansive soil cutting according to the slope ratio, and reserve 30-50cm for the thickness of backfilling planting soil;

(2) Determine the atmospheric influence depth of expansive soil according to the local expansive soil regional building technical specifications;

(3) Excavate the base elevation of the retaining wall to a position at least 0.5m above the atmospheric influence depth of the expansive soil, lay a layer of waterproof geotextile on the slope behind the wall, and then pour concrete for the retaining wall;

(4) When pouring the concrete of the retaining wall, the drain pipe 10 must be buried in the retaining wall. The drain pipe 10 is made of PVC pipe with a slope of 3%. After the retaining wall 1 is demolished, backfill the wall with permeable gravel of 20-30 cm and compact it; the embedding of the drain pipe 10 must have a certain slope for drainage;

(5) Excavate the beam groove on the slope according to the distance between the two nodes of the sash beam 2.5-3.5m. The size of the beam groove is a rectangular section with a width of 20cm and a depth of 30cm. After the beam groove is excavated, lay a flexible mesh geogrid Grid 4, then place the reinforcement cage, pour concrete, before pouring concrete, must reserve the anchor rod hole 17 at the sash beam 2 nodes;

(6) When the concrete of the sash beam 2 reaches the design strength, drill a hole vertically at the reserved anchor hole. The depth of the hole must be more than 1m greater than the atmospheric influence depth of the expansive soil, and then pour cement mortar into the hole to place the anchor 3. Insert it into the hole, and fix it with the anchor plate 16 and the nut 15 at the end of the anchor rod 3, and then pour concrete to seal the anchor head;

Fill the anchor head with concrete to prevent corrosion. After the construction of the sash beams and anchor rods, lay a layer of planting soil (non-expansive soil) on the slope, sow grass seeds suitable for the area in the planting soil, and plant shrubs suitable for the area after the planting grass survives. After the shrubs survive, plant trees suitable for the area. In this way, herbaceous plants (root system can reach 20-30cm) can prevent rain from washing the slope, shrubs (root system can reach 60-70cm) and trees (root system can reach 100- 150cm or more) The well-developed root system can fix the slope, reduce the evaporation of water in the slope, maintain the water balance in the slope, and effectively protect the slope, and green the slope to beautify the road appearance;

(7) Excavate the intercepting ditch or drainage ditch 7 at the top of the slope to the design elevation, then lay a layer of waterproof geotextile I6, and build the intercepting ditch or drainage ditch 7 on the waterproof geotextile I6;

(8) Backfill the slope with 30-50cm thick planting soil, and plant vegetation 5 on the planting soil: grass, shrubs and trees.

In step (5), the steel bar spacing of the steel cage is 10-15cm.

In step (5), the anchor hole 17 is a PVC pipe with a diameter of 5 cm.

After the drainage seepage ditch 12 is constructed, the drainage ditch 14 is built. It is suggested here that the road bed of the road cutting should be replaced with soil with better physical properties (or improved treatment of expansive soil), and then paved with waterproof geotextile together with the surface of expansive soil at the bottom of drainage ditch 12, which has achieved the effect of overall waterproofing .

Claims (9)

1. a Cut Slopes of Expansive Soil supporting and protection structure, it comprises rigid support system, flexible protective system and waterproof and water drainage system three parts, it is characterized in that:

Described rigid support system is that it comprises and is arranged on the crippled retaining wall of Cut Slopes of Expansive Soil (1) and retaining wall foundation;

It comprises described flexible support system the sash beam (2), the anchor pole (3) that are arranged on Cut Slopes of Expansive Soil, is laid on the flexible netted geo-grid (4) on domatic and is planted in the vegetation (5) on domatic;

It comprises the pervious layer (8) being arranged on after the catchwater on slope top or gutter (7), retaining wall, the draining sewer (12) under gutter (14) and gutter (14) described waterproof and water drainage system.

2. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, the position of above-mentioned retaining wall (1) substrate absolute altitude it is characterized in that: more than must affect degree of depth 0.5m over this region expansive soil body atmosphere, and the natural bearing capacity of substrate must be greater than 200kpa, retaining wall (1) adopts sheet stone concrete, and concrete intensity must be not less than C20.

3. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, is characterized in that: more than its anchorage depth of described anchor pole (3) must affect degree of depth 1m over this region expansive soil body atmosphere, bolt diameter is the indented bars that is not less than 16mm.

4. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, is characterized in that: the internodal distance of described sash beam (2) is 2.5-3.5m, and sash beam (2) consists of steel concrete, and concrete strength label is C20.

5. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, it is characterized in that: it is the direction earthwork grille of 20cm*20cm or 30cm*30cm that described flexible netted geo-grid (4) adopts size of mesh opening, every geo-grid adopts U-shaped draw-in groove to be connected and fixed, all geo-grid are linked to be to an integral body, make itself and sash anchor beam jointly form flexible supporting structure.

6. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, is characterized in that: the bottom of trench of described catchwater or gutter (7) is laid one deck waterproof geotextiles I (6).

7. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, is characterized in that: the wall top of described retaining wall (1) arranges the groove of inverted trapezoidal, and groove dimensions is dark 30-40cm, upper wide 40-50cm, lower wide 30-40cm.

8. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, it is characterized in that: in described retaining wall (1) depths, bury tapping pipe (10) underground, tapping pipe (10) wraps up by permeable geotextiles in the one end by retaining wall (1), and the other end of tapping pipe (10) is connected to draining sewer (12).

9. Cut Slopes of Expansive Soil supporting and protection structure according to claim 1, it is characterized in that: at described draining sewer (12), by waterproof geotextiles III (11), be laid on its expansive soil surface, in the middle of draining sewer (12), bury drain-hose (13) underground, drain-hose (13) wraps up by permeable geotextiles.

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