CN110984186B

CN110984186B - Self-water-absorption composite geogrid

Info

Publication number: CN110984186B
Application number: CN201911165290.4A
Authority: CN
Inventors: 陈庚
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2021-04-27
Anticipated expiration: 2039-11-25
Also published as: CN110984186A

Abstract

The invention discloses a self-water-absorption composite geogrid, which belongs to the technical field of geotechnical engineering and comprises a plurality of transverse ribs arranged at equal intervals and a plurality of longitudinal ribs arranged at equal intervals, wherein the transverse ribs and the longitudinal ribs are vertically crossed to weave the self-water-absorption composite geogrid; water absorbing materials are embedded in the transverse ribs and the longitudinal ribs. The invention has the following advantages: 1) water absorption: the rib material contains a water-absorbing material, so that accumulated water with low water level in the reinforced layer can be sucked out, and the influence on the soil stability caused by the accumulated water and the drainage consolidation time of the lower soil are reduced; 2) water permeability: the geogrid forms a drainage net by adding the water absorbing material in the ribs, and drainage of a treatment layer is not required to be carried out by combining the geotextile; 3) drainage property: according to the water loss characteristic of the high molecular water absorbing material after airing, when the self-water absorbing composite geogrid is used, part of the self-water absorbing composite geogrid is reversely wrapped on the surface layer of the dam for airing and draining; the water at the bottom of the dam is discharged outside through the self-water-absorption composite geogrid without prepressing.

Description

Self-water-absorption composite geogrid

Technical Field

The invention belongs to the technical field of civil engineering, and particularly relates to a self-water-absorption composite geogrid.

Background

In the projects of dams, embankments, revetments and the like, when the stress borne by the soil body exceeds the elastic strain range, large plastic strain is generated until the soil body is damaged; or under the action of long-term stress, the soil body generates certain creep and relaxation phenomena, and accidents such as soil body cracking, overlarge displacement and even collapse can be induced. Therefore, geogrids are often arranged in soil bodies at present to change stress fields and strain fields in a treatment range and stress states of the soil bodies, so that the soil bodies are reinforced, the displacement and uneven displacement of the soil bodies are reduced, and the stability is enhanced.

Currently, there are a number of geogrids available: plastic geogrids, warp-knitted geogrids, composite bidirectional geogrids, bidirectional steel-plastic geogrids, steel wire grids and the like. The design thought mainly focuses on the use of new materials, new warp and weft structures and new node design to achieve the purposes of enhancing the tensile property, integrity and durability of the geogrid, the existing composite geotextile is subjected to reinforcement design mainly by considering the strength requirement of the geotextile, the geotextile such as reinforced geotextile and composite geotextile and the like are simply bonded with the geogrid, and relevant design and research on the water absorption of the geogrid are not provided.

However, the water absorption of geogrids has a great engineering requirement, for example, when road construction is performed on a soft foundation, geogrid reinforced cushion layers are often adopted to reduce the lateral displacement, vertical settlement and uneven settlement of the upper embankment, and along with filling of overlying filling and consolidation settlement of a soft foundation, the cushion layers can generate a settlement curve of a settlement basin, that is, settlement near the center line of the embankment is large and settlement of two ends of the roadbed is small. Due to the existence of the sedimentation basin, water discharged by soft foundation solidification cannot be discharged in time through the cushion layer and accumulates at the bottom layer of the sedimentation basin, so that the prepressing time is influenced, and post-construction uneven sedimentation of the embankment is possibly generated; when the side slope is reinforced and the retaining wall is reinforced, the geogrid is adopted for reinforcement to enhance the stability of the side slope retaining wall, the influence of the water content of the side slope soil body on the self stability of the side slope retaining wall is obvious for unsaturated soil bodies, and if a plurality of reinforced side slopes have no drainage channels in the side slopes due to long-term rainfall, the shear strength of the soil body is reduced, and side slope landslide is generated.

In summary, there is a need for a geogrid with a water absorption function to solve the engineering problem caused by the failure of timely water drainage due to the independent use of the geogrid.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a self-water-absorption composite geogrid, which solves the engineering problem that free water accumulation in a processed soil body cannot be timely removed due to the non-water absorption of a reinforced material when the geogrid is simply used, such as the influence of water accumulation of a basin bottom cushion layer in a settlement basin of an embankment on lower soft foundation consolidation and the influence of continuous rainfall on the stability of side slope reinforcement of the geogrid.

The technical scheme is as follows: in order to achieve the purpose, the invention provides the following technical scheme:

a self-water-absorption composite geogrid comprises a plurality of transverse ribs arranged at equal intervals and a plurality of longitudinal ribs arranged at equal intervals, wherein the transverse ribs and the longitudinal ribs are vertically intersected to form the self-water-absorption composite geogrid; and water absorption materials are embedded in the transverse ribs and the longitudinal ribs.

Furthermore, the upper part and the lower part of the water absorbing material are clamped by two layers of grid strength materials.

Furthermore, a permeable filter membrane is arranged between the grid strength material and the water absorption material.

Furthermore, the adhesion mode of the permeable filter membrane and the grid strength material is in a concave shape, so that a hollow part of the grid strength material on the outer side is formed, and the foundation water enters the water absorption material through the permeable filter membrane.

Further, the grid strength material is selected from any one of polyester fiber, glass fiber and carbon fiber.

Furthermore, the water absorption material is bonded with the grid strength material and the water permeable filter membrane by using hot melt or chemical reagents.

Has the advantages that: compared with the prior art, the self-water-absorption composite geogrid disclosed by the invention has the following advantages:

1) water absorption: the rib material contains a water-absorbing material, so that accumulated water with low water level in the reinforced layer can be sucked out, and the influence on the soil stability caused by the accumulated water and the drainage consolidation time of the lower soil are reduced;

2) water permeability: the geogrid forms a drainage net by adding the water absorbing material in the ribs, and drainage of a treatment layer is not required to be carried out by combining the geotextile;

3) drainage property: according to the water loss characteristic of the high molecular water absorbing material after airing, when the self-water absorbing composite geogrid is used, part of the self-water absorbing composite geogrid is reversely wrapped on the surface layer of the dam for airing and draining; the water at the bottom of the dam is discharged outside through the self-water-absorption composite geogrid without prepressing.

Drawings

FIG. 1 is a top view of a self-priming composite geogrid;

FIG. 2 is a top view of a self-priming composite geogrid rib;

FIG. 3 is a cross-sectional view of a self-priming composite geogrid rib;

FIG. 4 is a schematic representation of the use of a self-priming composite geogrid in dam construction;

reference numerals: 1-transverse ribs; 2-longitudinal ribs; 3-a water-absorbing material; 4-grid strength material; 5-a water-permeable filter membrane; 6-embankment; 7-self water-absorption composite geogrid; 8-foundation.

Detailed Description

The invention will be further described with reference to the following drawings and specific embodiments.

As shown in fig. 1-3, a self-water-absorption composite geogrid comprises a plurality of equally spaced transverse ribs 1 and a plurality of equally spaced longitudinal ribs 2, wherein the transverse ribs 1 and the longitudinal ribs 2 are vertically crossed to form a self-water-absorption composite geogrid 7. The transverse ribs 1 and the longitudinal ribs 2 respectively comprise water absorption materials 3, grid strength materials 4 and permeable filter membranes 5.

Water absorbing materials 3 are embedded in the transverse ribs 1 and the longitudinal ribs 2, the upper portions and the lower portions of the water absorbing materials 3 are clamped by two layers of grid strength materials 4, and water permeable filter membranes 5 are arranged between the grid strength materials 4 and the water absorbing materials 3. The adhesion mode of the permeable filter membrane 5 and the grid strength material 4 is in a concave shape, namely the hollow part of the grid strength material 4 at the outer side can ensure that the foundation water enters the water absorption material 3 through the permeable filter membrane 5.

The grid strength material 4 is mainly polyester fiber (or glass fiber and carbon fiber), and the water absorbing material 3 is bonded to the grid strength material 4 and the water permeable filter membrane 5 by using hot melt or chemical reagents.

The working process is as follows: the water in the foundation 8 gets into water absorption material 3 through the filter membrane 5 that permeates water, because of the characteristic of the compound geogrid 7 of self absorption water, can be with subsiding the accumulation water absorption of pelvic floor to embankment 6 both sides, again by the anti-complex geogrid 7 of self absorption water of embankment 6 of turning up, utilize the grid sunning of turning up embankment 6, effect drainage such as air-dry to accelerate the drainage rate of horizontal bed course, reduce embankment 6's pre-compaction time and uneven settlement. And absorbing water in the water absorbing materials of the grids of the sedimentation basin to the two sides of the embankment 6 by the water absorption of the grids, then utilizing the grids of the reverse embankment 6 for airing, air drying and other drainage, continuously settling the grids at the bottom of the basin to absorb water by the grids at the two sides of the aired embankment 6, then airing and other drainage, and repeating the steps.

As shown in fig. 4, due to the pre-pressure action of the embankment 6, a "sedimentation basin" is formed on the surface of the foundation 8, wherein the sedimentation is large at the corresponding part of the center of the embankment 6 and small at the two ends, and water drained from the foundation 8 due to the load action of the upper embankment 6 is accumulated at the bottom of the sedimentation basin and cannot be drained.

In the embodiment, a self-water-absorption composite geogrid 7 is adopted, the grid intervals are 10cm, and the rib width is 1 cm. The cross section of the rib is shown in figure 3, wherein the grid strength material 4 is made of polyester fiber, and the water permeable filter membrane 5 is a non-woven filter membrane with O95 being less than 0.075 mm; the water absorbent material 3 is water absorbent resin. The top view of the ribs is shown in fig. 2, the width of the grid strength material 4 is 2 x 0.25mm, and the exposed width of the geotechnical water-permeable filter membrane 5 is 0.5 mm. The breaking elongation of the grating is less than or equal to 3 percent, the longitudinal tensile strength is more than or equal to 80kN/m, and the transverse tensile strength is more than or equal to 80 kN/m.

Claims

1. The utility model provides a compound geogrid of self priming which characterized in that: the self-water-absorbing composite geogrid comprises a plurality of transverse ribs (1) arranged at equal intervals and a plurality of longitudinal ribs (2) arranged at equal intervals, wherein the transverse ribs (1) and the longitudinal ribs (2) are vertically crossed to weave a self-water-absorbing composite geogrid (7); the water absorption materials (3) are embedded in the transverse ribs (1) and the longitudinal ribs (2); the upper part and the lower part of the water absorbing material (3) are clamped by two layers of grid strength materials (4); a permeable filter membrane (5) is arranged between the grid strength material (4) and the water absorption material (3); the grid strength material (4) is selected from any one of polyester fiber, glass fiber and carbon fiber; the permeable filter membrane (5) and the grid strength material (4) are adhered in a concave shape to form a hollow part of the grid strength material (4) at the outer side, so that the foundation water enters the water absorbing material (3) through the permeable filter membrane (5); the water absorbing material (3) is bonded with the grid strength material (4) and the permeable filter membrane (5) by using hot melt or chemical reagents; the water absorbing material (3) adopts water absorbing resin; the width of the transverse ribs (1) and the width of the longitudinal ribs (2) are 1 cm; the width of the grid strength material (4) is 2mm, and the thickness is 0.25 mm; the self-water-absorption composite geogrid (7) is arranged at the bottom of a sedimentation basin of the embankment (6) and is reversely wrapped at two sides of the embankment (6); because the hydroscopicity of the compound geogrid of self absorption water (7), the compound geogrid of self absorption water (7) will subside the accumulational water absorption of pelvic floor portion to embankment (6) both sides, recycle the compound geogrid of self absorption water (7) sunning, the air-dry effect drainage of anti-package in embankment (6), self absorption water compound geogrid (7) of embankment (6) both sides after drying continue to absorb water from the compound geogrid of self absorption water (7) of subsiding the pelvic floor portion, sunning again, air-dry the drainage.