CN107326914B

CN107326914B - Dead weight anchoring type geogrid reinforced soil structure and construction method thereof

Info

Publication number: CN107326914B
Application number: CN201710554976.7A
Authority: CN
Inventors: 刘龙武
Original assignee: Changsha University of Science and Technology
Current assignee: Changsha University of Science and Technology
Priority date: 2017-07-10
Filing date: 2017-07-10
Publication date: 2019-12-27
Anticipated expiration: 2037-07-10
Also published as: CN107326914A

Abstract

The invention discloses a dead weight anchoring type geogrid reinforced soil structure and a construction method thereof. The self-weight anchoring type geogrid reinforced soil structure consists of 5 parts including a bottom cushion layer 1, a bottom drainage layer 2, a self-weight anchoring type geogrid reinforced soil layer, a middle drainage layer 11, a platform and a slope surface grass planting layer 12. The dead weight anchoring type geogrid reinforced soil layer is composed of an inner layer anchoring section 14 and an outer layer section 15, the inner layer geogrid 3 of the inner layer anchoring section 14 provides anchoring force for the outer layer geogrid 7 of the outer layer section 15, the defect that a reinforced soil structure is difficult to effectively use due to insufficient reinforced soil interface friction strength of ribs and soil materials such as cohesive soil and glass fiber geogrids is overcome, and the method is particularly suitable for reinforcing wet clay side slope water-damaged landslides such as coal strata and red clay.

Description

Dead weight anchoring type geogrid reinforced soil structure and construction method thereof

The technical field is as follows: the invention relates to a reinforced soil structure and a construction method thereof, in particular to a dead weight anchoring type geogrid reinforced soil structure and a construction method thereof.

Background

Coal strata, red clay and the like in the south of China are used as special soil which is widely distributed in the south of China and has certain expansibility, water damage such as shallow gradual landslide and the like is generally induced under the humidification and the subsurface corrosion of upper-layer local stagnant water formed by dehydration drying and rainfall infiltration of an excavated slope surface, a landslide soil body with high water content is formed, and the traditional reinforcement method is difficult to economically and effectively treat.

If the reinforced soil structure is adopted for reinforcement, the wet coal-series stratum and the wet red clay slope collapsed soil have high water content, the friction strength between the soil and the geogrid is too low, effective anchoring force is difficult to form, and the geogrid reinforced soil structure is difficult to realize the reinforcement effect. Therefore, in order to use wet clay as a filler for a geogrid reinforced earth structure, it is necessary to overcome the problem that it is difficult to form effective geogrid anchoring strength due to a low friction coefficient between the clay and the geogrid. By developing a novel geogrid reinforced earth structure which has high construction speed, good economical efficiency and environmental protection and can utilize wet clay, a novel effective treatment method can be provided for the common water-damaged landslide damage treatment problem of special earth of coal strata and red clay in south China,

disclosure of Invention

The technical problem to be solved by the invention is that the wet clay and the geogrid have low friction coefficient and are not suitable for being used as reinforced earth filler. The invention aims to solve the problem that effective anchoring strength is difficult to form between wet clay and the geogrid through a reasonably designed dead weight anchoring type geogrid reinforced earth structure.

According to the invention, the two ends of the annular geogrid 3 wrapped with the compacted clay are connected by the connecting rods 5 at the inner-layer anchoring section 14 to form the geogrid annular wrapping bag (figure 1), so that the total anchoring force of the outer-layer geogrid can be formed on the annular geogrid 3 by utilizing the self weight of the compacted clay soil body 4 and the self weight 19 of the upper soil body. The anchoring force 23 provided by the annular geogrid 3 in the inner layer anchoring section 14 to the geogrid 7 of the outer layer section 14 consists of 3 parts, namely anchoring force 20 on the top surface of the annular geogrid 3, anchoring force 21 on the bottom surface of the annular geogrid 3 and anchoring force 22 provided by lateral earth pressure on the side surface of the annular geogrid 3. Wherein, the anchoring force 22 provided by the lateral soil pressure on the side surface of the annular geogrid 3 is the anchoring force which does not exist in the traditional geogrid reinforced soil, and the anchoring force 22 makes up the deficiency of the friction strength between the wet clay and the geogrid of the anchoring section.

According to the invention, the head ends of the geogrids 7 of the outer layer section are connected by the connecting rods 8 through the layer heights 2/3 above the outer sides of the annular geogrids 3 in the inner layer anchoring sections 14 of the next layer, after soil covering, compaction and reverse wrapping, the tail ends of the geogrids 7 are connected by the connecting rods 9 and the connecting rods to the layer heights 2/3 above the outer sides of the annular geogrids 3 in the inner layer anchoring sections 14 of the previous layer, so that a staggered structure of the outer layer section 15 and the inner layer anchoring sections 14 is formed, and the staggered structure is beneficial for the anchoring sections to exert larger anchoring force; the invention further ensures the horizontal stability of the geogrid reinforced earth structure by setting the design requirement that the width of the inner layer anchoring section 14 is larger than that of the outer layer turn-up free section 15, and strengthens the structural stability of the geogrid reinforced earth structure in the vertical direction by arranging the middle drainage layer 11 between every two layers of the self-weight anchoring type geogrid reinforced earth layers.

The invention provides a self-weight anchoring type geogrid reinforced soil structure, which is a novel geogrid reinforced soil structure capable of overcoming the defects that the friction coefficient between an anchoring section geogrid and an over-wet clay filler is low and effective anchoring strength is difficult to form, is suitable for common water-damaged landslide damage treatment of coal strata and red clay special soil in south China, and is high in construction speed, economic and environment-friendly.

Drawings

Fig. 1 is a schematic view of a deadweight anchored type geogrid reinforced soil structure.

Concrete construction method

By combining construction practices of a self-weight anchoring type geogrid reinforced soil structure by adopting over-wet red clay soil after landslide in 2016 (1-6), referring to fig. 1, the specific construction method of the self-weight anchoring type geogrid reinforced soil structure has the following steps:

(1) removing a shallow sliding slope body of the slope, and excavating according to design requirements to the bottom of the dead weight anchoring type geogrid reinforced soil structure;

(2) excavating red clay soil materials in a coal-series stratum by adopting an excavator, mixing the red clay soil materials and cement into cement modified soil materials at the site according to the weight ratio of 5-8%, and filling a bottom cushion layer 1 by using the cement modified soil materials according to the width of not less than 4m and the thickness of not less than 0.5 m;

(3) paving a gravel soil or gravel soil layer 2, an inner anchoring section 14 with the thickness of 15cm and an outer section 15 with the thickness of 50cm in sequence;

(4) laying a first inner geogrid 3 on an inner-layer anchoring section 14 of a gravel soil or gravel soil layer 2, reserving the first inner geogrid 3 to be reversely wrapped to a length required by connection, filling a layer of red clay soil material with the thickness of 0.5m on the laying range of the inner-layer anchoring section 14, compacting to obtain an inner compaction layer 4 of the inner-layer anchoring section 14, reversely wrapping the first inner geogrid 3, and connecting two ends of the first inner geogrid 3 into a ring shape by using a connecting rod 5, so that the construction of a first geogrid reinforced soil layer of the inner-layer anchoring section 14 is completed;

(5) laying a first outer layer geogrid 7 on an outer layer section 15 of the gravel soil or gravel soil layer 2, connecting the head end of the first outer layer geogrid 7 with the first inner layer anchoring section 14 at the 2/3-layer high position of the side wall of the first inner layer anchoring section 14 by using a connecting rod, and reserving a length required by bidirectional reverse wrapping;

(6) completing the construction of the upper geogrid reinforced soil layer of the inner-layer anchoring section 14 according to the step (4);

(7) paving a layer of red clay soil material with the thickness of 0.5m above the paving range of the outer layer section 15, compacting to obtain an outer compacted layer 10 of the outer layer section 15, reversely wrapping the tail end of the outer geogrid 7, and connecting the tail end of the outer geogrid 7 to 2/3-layer high positions on the side wall of the upper inner anchoring section 14 by using a connecting rod 9, so that the construction of the first geogrid reinforced soil layer of the outer layer section 15 is completed, and the second geogrid reinforced soil layer of the inner anchoring section 14 and the first geogrid reinforced soil layer of the outer layer section 15 form a first self-weight anchoring type geogrid reinforced soil layer with a staggered structure;

(8) paving a gravel soil or gravel soil layer 11 with the thickness of 15cm on the first self-weight anchoring type geogrid reinforced soil layer with the staggered-layer structure and compacting, thereby completing the construction of the first self-weight anchoring type geogrid reinforced soil unit layer;

(9) repeating the construction method of the steps (4) to (6), and repeating the construction of the step (7) twice and the construction of the step (8) once to finish the construction of a second self-weight anchoring type geogrid reinforced earth unit layer;

(10) repeating the construction method of the step (9) for 4 times, namely completing the construction of all the dead weight anchoring type geogrid reinforced soil unit layers;

(11) a layer of waterproof geotextile 16 is paved on the top of the dead weight anchoring type geogrid reinforced soil unit layer according to the reverse slope rate 13 of 10 percent, and the geotextile is covered with planting loam with the thickness of 30 cm;

(12) and constructing the slope vegetation layer 12, the slope bottom drainage ditch 17 and the slope top drainage ditch 18 according to a conventional method.

Claims

1. A construction method of a dead weight anchoring type geogrid reinforced soil structure is characterized by comprising the following construction steps:

(2) excavating red clay soil materials in a coal-series stratum by adopting an excavator, mixing the red clay soil materials and cement into cement modified soil materials at the site according to the weight ratio of 5-8%, and filling a bottom cushion layer (1) by using the cement modified soil materials according to the width of not less than 4m and the thickness of not less than 0.5 m;

(3) paving a gravel soil layer or gravel soil layer (2), an inner-layer anchoring section (14) with the thickness of 15cm and an outer-layer section (15) with the thickness of 50cm in sequence;

(4) laying a first inner-layer geogrid (3) on an inner-layer anchoring section (14) of a gravel soil or gravel soil layer (2), reserving the first inner-layer geogrid (3) to be reversely wrapped to a length required by connection, filling a layer of red clay soil material with the thickness of 0.5m on the laying range of the inner-layer anchoring section (14), compacting to obtain an inner compaction layer (4) of the inner-layer anchoring section (14), reversely wrapping the first inner-layer geogrid (3) and connecting two ends of the first inner-layer geogrid with connecting rods (5) to form a ring, so that the construction of the first-layer geogrid reinforced soil layer of the inner-layer anchoring section (14) is completed;

(5) laying a first outer-layer geogrid (7) on an outer-layer section (15) of the gravel soil or gravel soil layer (2), connecting the head end of the first outer-layer geogrid (7) with the first inner-layer anchoring section (14) by using a connecting rod at the 2/3-layer height of the side wall of the first inner-layer anchoring section (14), and reserving a bidirectional reverse wrapping to the length required by connection;

(6) completing construction of a geogrid reinforced soil layer on the inner-layer anchoring section (14) according to the step (4);

(7) paving a layer of red clay soil material with the thickness of 0.5m on the paving range of the outer layer (15), compacting to obtain an outer compaction layer (10) of the outer layer (15), reversely wrapping the tail end of the outer geogrid (7), and connecting the tail end of the outer geogrid (7) to 2/3 high positions of the side wall of the upper inner anchoring section (14) by using a connecting rod (9), so that the construction of the first geogrid reinforced soil layer of the outer layer (15) is completed, and the second geogrid reinforced soil layer of the inner anchoring section (14) and the first geogrid reinforced soil layer of the outer layer (15) form a first self-weight anchoring type geogrid reinforced soil layer with a staggered structure;

(8) paving a gravel soil layer (11) with the thickness of 15cm on the first self-weight anchoring type geogrid reinforced soil layer with the staggered layer structure and compacting, thereby completing the construction of the first self-weight anchoring type geogrid reinforced soil unit layer;

(11) paving a layer of waterproof geotextile (16) on the top of the dead weight anchoring type geogrid reinforced soil unit layer according to a reverse slope rate (13) of 10%, and covering the geotextile with the thickness of 30 cm;

(12) and constructing a slope vegetation layer (12), a slope bottom drainage ditch (17) and a slope top drainage ditch (18) according to a conventional method.