RU2337205C1 - Method of earthwork fabric on weak natural basis - Google Patents

Abstract

FIELD: construction; mining.

SUBSTANCE: on collapsing soils having considerable depth there are constructed vertical banded geological absorbing wells and piles in the form of excision, where is introduced reinforcing agent, providing simultaneously ground fluid filtration. Into excisions of geological absorbing wells and piles reinforcing agent is introduced with vibropiling and combined with area seal of grounds. Excision of geological piles is filled by portion filling. Each filled portion is vibropiled.

EFFECT: strengthening of weak base of collapsing soils.

4 cl, 7 dwg

Description

The invention relates to road construction, and more specifically relates to a method of erecting an earthen structure, mainly for railways and roads, built on a weak natural base, mainly composed of subsiding soils to a significant depth of about 30 meters.

The method can also be used in the construction of dams, dams, etc.

There is a method of constructing a road subgrade on a weak foundation with the installation of concrete or cement hard piles (Manual on the design of the subgrade of roads on soft soils. - M., Informavtodor, 2004, p.77-89).

The known method has disadvantages, which are manifested in significant consumption of cement and the use of heavy reinforced concrete structures.

In addition, due to the different bearing capacity in the inter-pile space, uneven precipitation and rupture of the geotextile as a flexible grillage are possible.

The closest is the known method of construction of the roadway, mainly on soft soils (RF patent No. 2273687), in which they perform the foundation in the soil, drainage ditches along the base and place a reinforcing device on the base. An embankment is built on top of the reinforcing device. For the reinforcing device, drainage slots are made across the roadway with a calculated step and width, determined by the achievement of soil consolidation in the construction period, and a depth to the level of the soil, which has filtration properties and sufficient bearing capacity. The drainage slots are covered with a sand-gravel mixture and a reinforcing layer is placed on them, which provides simultaneous filtering of the liquid in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway. The reinforcing layer is covered with a sand-gravel mixture, which is compacted, and then the embankment is covered with layers. Each sprinkled layer is sealed by vibration sealing.

The known method has disadvantages, which are manifested in insufficient compaction of soils to obtain a reliable arrangement of railways, roads, dams, dams, etc., built on a weak natural foundation, mainly composed of subsidence soils to a significant depth of about 30 m

The basis of the invention is the task of increasing the reliability of the device earthworks for railways, roads, dams, dams, etc., built on a weak natural foundation, mainly composed of subsiding soils to a significant depth of about 30 m

EFFECT: strengthening of weak foundations, mainly from subsidence soils, by constructing a reinforcing device containing geo-drains and geo-piles with deep compaction of soils.

The problem is solved in that in the method of erecting an earthen structure on weak natural foundations, mainly for railways and roads, including making the foundation and reinforcing device in the soil and placing the embankment on top of the reinforcing device, with vibration compaction, on subsiding soils having a significant depth, vertical tape geodrains and geo-piles in the form of recesses in which reinforcing material is introduced, simultaneously iltratsiyu dirt liquid, wherein the recesses and the vertical tape geodren geosvay reinforcing material is introduced with vibro and combine it with the sealing surface soils. It is advisable that the excavation of the geo-piles be filled with dumping portions, while each packaged portion is vibro-compacted. Placement of geodrains in the plan is performed in the form of a rhombus or square with a step of 1 to 3 m.

Placement of geo-piles in the plan is performed in the form of a rhombus or square in increments of 6.0 to 8.5 m.

The invention is further illustrated by the drawings in which:

Figure 1 shows the transverse profile of the earthen construction of the roadway, according to the invention.

Figure 2 shows a plan of a reinforced base and passages for a vibratory roller.

Figa-3b illustrate the construction of geodrains and devices for construction. Figures 4a-4b illustrate the construction of a geo-pile and a device for construction.

Figure 5 illustrates the deep compaction of the geo-pile stepwise in combination with vibration compaction of the base.

Earthwork is erected as follows.

On the right of way from shrubs and trees, the right-of-way layer is cut out (see Fig. 1). The preferred depth of cut is 0.3-0.5 m. The cut soil and plant layer is replaced by a drainage layer 1 of a sand-gravel mixture (hereinafter referred to as ASG) and geotextile 2.

On the sides of the right of way, drainage ditches 3 are arranged. The depth and width of the drainage ditches 3 are determined according to the regulated hydrological conditions of the terrain and the filtration characteristics of the soils. Drainage ditches 3 can be filled with ASG.

The resulting site is broken down for the installation of vertical tape geodrains 4 and geo-piles 5.

To do this, first develop a plan for the reinforced base and passages for the vibratory roller (figure 2).

The device of vertical tape geodrains and geo-piles is carried out to harden the soils of a weak base. Depending on the properties of subsiding soils and its depth, vertical tape geodrains and geo-piles can be supported (to the full extent, to the mineral bottom) and suspended.

The device geodrain and geosvay also serves to reduce water cut and drainage of pore water.

The decisive factor in determining the distance between geodrains and geo-piles is the filtration properties of soils.

The placement of vertical tape geodrains 4 in the plan is performed in the form of a rhombus or square with a preferred step of 6 from 1.0 to 3.0 m.

The arrangement of geo-piles 5 in the plan is also performed in the form of a rhombus or square with a preferred step of 7 from 6 to 8.5 m.

Then, from the surface of the prepared base, first, the device of vertical tape geodrains 4, and then the device of geo-piles 5. For the device of vertical tape geo-drains 4 and geo-piles 5, special devices are used.

The device vertical tape geodrain 4 is carried out using a special device (figa) based on an excavator.

A device for constructing a geodrain includes a mast 9, on which a hollow casing 10 is mounted, over which a vibratory driver 11 is mounted. At the bottom of the mast 9, a roll drain 8 is attached, and a tape drain 12 is passed through the top of the mast 9 and inside the casing 7, which is attached to the anchor anchor 13. The anchor anchor is made in the form of a metal plate with two holes for which the tape drain 12 is hooked.

The tape drain 12 (Fig. 3b) is a composite material consisting of a plastic core 14 wrapped in nonwoven geotextile 15 to prevent siltation of the core. The width of the core is about 100 mm, the height is 3-4 mm.

The device is used for the construction of a vertical tape geodrain 4 as follows.

Anchor anchor 13 with a fixed drain 12 vibro-immersed casing 10 is pressed into a weak base. The depth of indentation is determined by the properties of soils. Deepening lead up to the design level and it can reach strong soils.

After reaching the design depth, the casing 9 is removed. Anchor anchor 13 with a tape drain 12 is left in the ground as a vertical tape geodrain 4.

The process of installing vertical tape geodrains 4 is carried out in places according to the plan.

A device for the construction of geo-piles 5 (figa) is carried out using a machine 16 with vibration equipment.

The vibration equipment consists of a mast 17, on which a hollow casing pipe 18 is mounted with an opening cone 19 installed in the lower part of the casing pipe 18, and a vibro-driver mounted above the casing pipe 18 (not shown).

The diameter of the hollow casing is from 300 to 900 mm.

The device is used for the construction of geo-piles 5 as follows.

Immerse the casing 18 into the ground with a vibratory driver to the design depth. Then, through the top, the space of the casing 18 is filled with material: sand, ASG, crushed stone, etc.

The supply is provided, for example, by a conveyor (not shown in FIG. 4a).

After filling, open the cone 19 and take out the casing 18 with vibration of the vibrator for uniform compaction of the formed geological pile 5 over the entire depth.

It is advisable to fill the geo pile with sprinkling of material in portions, while vibro-compaction of each sprinkled portion (figure 5).

After filling each individual portion of the material, the cone 19 is opened and the casing 18 is slowly removed to the depth of the filling. Then the cone 19 is closed. The filled portion is compacted by vibration. After that, open the cone 19 and repeat the operation until the complete construction of the geological pile 5.

The construction of vertical tape geodrains 4 and geo-piles 5 is performed in combination with surface vibration compaction of soils with a vibratory roller from the surface of the base.

When erecting an earthen structure over geodrains 4 and geo-piles 5, a drainage layer 20 is made of a sand-gravel mixture reinforced with geotextiles, providing water filtration in all directions without changing the properties of the reinforcing device under load.

The drainage layer is compacted with a vibratory roller in an adjustable mode until a predetermined filtration consolidation of the base is achieved, then the embankment 21 is poured in layers, and each dumped layer is compacted with a vibration seal.

The proposed method was experimentally applied and gave a good result of hardening a weak base during the construction of a section of road approaches to the bridge over the river. Kama for the embankment with a height of 6 m to 8 m with a weak base thickness of 4 m to 9 m.

During vibration compaction, vibration load correction was performed to select the optimal compaction mode and the calculated safety factor.

Claims (4)

1. A method of erecting an earthen structure on weak natural foundations, mainly for railways and roads, comprising making a foundation and a reinforcing device in the soil and placing an embankment on top of the reinforcing device with vibration compaction, characterized in that on subsiding soils having a significant depth, for the reinforcing device in vertical tape geodrains and geo-piles are constructed in subsidence soil in the form of recesses into which reinforcing material is introduced, which simultaneously provides soil filtration liquid, moreover, reinforcing materials are introduced into the recesses of vertical tape geodrains and geo-piles with vibration absorption and combine it with surface soil compaction. 2. The method of erecting an earthen structure according to claim 1, characterized in that the excavation of the geo-piles is filled with dumping portions, while each portion is vibro-compacted. 3. The method according to claim 1 or 2, characterized in that the location of the geodrain in the plan is performed in the form of a rhombus or square in increments of 1 to 3 m. 4. The method according to claim 1 or 2, characterized in that the placement of geo-piles in the plan is performed in the form of a rhombus or square in increments of 6.0 to 8.5 m.

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