CN104790413B - A kind of maintain the stable self-pressurization preventer in swelled ground moat slope and method thereof - Google Patents

Abstract

The invention discloses a self-pressurizing protective device and method for maintaining the stability of expansive soil cutting slopes. The device includes an anchor rod, a first circular plate, a second circular plate, and a high-strength spring. The first circular plate and the second circular plate The circular plate is set on the anchor rod, a high-strength spring is arranged between the first circular plate and the second circular plate, a nut is arranged on the first circular plate, and the nut is fixedly sleeved on the anchor rod. Through the self-pressurizing device, the problem that the expansive soil cutting slope tends to be unstable under the action of the atmosphere is solved. It is suitable for various types of expansive soils. At the same time, the layout is simple, the construction operation is simple, and it can also be used for temporary protection. Its engineering The application prospect is broad. The function mechanism of the protection device conforms to the working law of expansive soil cutting slopes, and the engineering characteristics of expansive soils are fully considered in the protection design; the construction efficiency is high, the layout is flexible, and it is applicable to various soil layers; Using materials such as bamboo or wood has little impact on the environment.

Description

Self-pressurization protection device and method for maintaining stability of expansive soil cutting slope

technical field

The invention relates to construction technology in the field of civil engineering, and is mainly used for slope engineering design and construction, in particular to a self-pressurizing protective device and method for maintaining the stability of expansive soil cutting slopes.

Background technique

With the development of social economy, the operation or construction of a large number of roads, railways and water conservancy projects in expansive soil areas, as well as the construction process of urbanization in expansive soil areas, have created a large number of expansive soil cutting slopes. The formation process of expansive soil cutting slope is the result of human transformation of nature, which often destroys the original stable state of natural materials and lays hidden dangers for slope catastrophe. Under the influence of the atmosphere, as the number and magnitude of the dry-wet cycle increase due to evaporation and rainfall, the repeated expansion and contraction of the expansive soil will cause the soil to produce criss-cross cracks, the soil will become loose, and its strength will decrease. In addition, weathering will further destroy the The integrity of the soil makes the expansive soil cutting slope tend to be unstable, which in turn leads to failure. When the expansive soil bears the upper pressure, the expansion and contraction deformation of the soil caused by the dry-wet cycle will be greatly reduced, the dry density and crack changes of the soil can be effectively suppressed, and the attenuation of the soil strength will be greatly reduced. Therefore, the self-pressurization protection device and its method for maintaining the stability of expansive soil cutting slope can effectively maintain the strength of expansive soil and ensure the stability of cutting slope, and the construction method is simple, efficient, and flexible in layout, which can reduce engineering costs and expand application range.

Contents of the invention

1. Technical problems to be solved

Aiming at the problems existing in the prior art, the present invention provides a self-pressurizing protective device and method thereof for maintaining the stability of expansive soil cutting slopes, which is simple in structure, convenient for on-site operation, low in engineering cost, and conforms to the engineering characteristics of expansive soil.

2. Technical solution

The purpose of the present invention is achieved through the following technical solutions.

A self-pressurizing protection device for maintaining the stability of expansive soil cutting slopes, including anchor rods, first circular plates, second circular plates, and high-strength springs, the first circular plate and the second circular plate are sleeved on the anchor rods, A high-strength spring is provided between the first circular plate and the second circular plate, and a nut is provided on the first circular plate, and the nut is fixedly sleeved on the anchor rod.

The diameter of the first circular plate is smaller than the diameter of the second circular plate.

The depth of the anchor bolt embedded in the soil is 1.5-2 times the depth of severe atmospheric influence.

The distance between the first circular plate and the second circular plate is 0.2-0.5m.

A self-pressurization protection method for maintaining the stability of expansive soil cutting slope, characterized in that the steps include:

Step 1) Sampling on site, carrying out expansion and deformation tests, determining the expansion and deformation of soil samples when the soil sample is covered by 0kPa, 12.5kPa, 25kPa, 50kPa and 100kPa through indoor tests, and converting the upper expansion and deformation when the expansion and deformation are zero by interpolation. Overburden stress δ;

Step 2) convert the deformation s=(δ·A)/k of the spring through the overlying compressive stress δ, the second disc area A and the deformation coefficient k of the high-strength spring;

Step 3) Judging the depth d of the severe influence of the soil atmosphere on the basis of the building technical specifications in expansive soil areas;

Step 4) According to the depth d of severe atmospheric influence, consider the soil anchoring force F = 1.2 δ A, test the strength parameters c, φ of the soil in the anchorage area, and the friction coefficient μ of the anchor rod, and convert the anchor rod according to the specification. The length l below the depth where the atmosphere is strongly influenced;

Step 5) Determine the total length of the self-pressurizing device anchor rod L=l+d according to the length l of the anchor rod that needs to penetrate below the depth of the severe atmospheric influence, the depth d of the severe atmospheric influence, the spring deformation s, and the length m of the self-pressurizing device +m-s;

Step 6) The self-pressurizing devices of different combinations are hammered in, and the depth of the anchor bolt into the soil is D=l+d.

3. Beneficial effect

Compared with the prior art, the present invention has the advantages of:

Through the self-pressurizing device, the problem that the expansive soil cutting slope tends to be unstable under the action of the atmosphere is solved. It is suitable for various types of expansive soils. At the same time, the layout is simple, the construction operation is simple, and it can also be used for temporary protection. Its engineering The application prospect is broad. The function mechanism of the protection device conforms to the working law of expansive soil cutting slopes, and the engineering characteristics of expansive soils are fully considered in the protection design; the construction efficiency is high, the layout is flexible, and it is applicable to various soil layers; Using materials such as bamboo or wood has little impact on the environment.

Description of drawings

Fig. 1 is a schematic diagram of a single spring structure of the present invention.

Fig. 2 is a schematic diagram of the position of the spring in Fig. 1 .

Fig. 3 is a schematic diagram of multiple groups of springs in the present invention.

Fig. 4 is a schematic diagram of the position of the spring in Fig. 3 .

Fig. 5 is a schematic diagram of the installation of the present invention.

Fig. 6 is a schematic diagram of the slope layout of the present invention.

Fig. 7 is a schematic diagram of grouping types in the present invention.

In the figure: 1. Anchor rod 2. The first circular plate 3. The second circular plate 4. High-strength spring 5. Nut.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The invention belongs to a new device and new method for protection of expansive soil cutting slope engineering. Aiming at the catastrophic characteristics of expansive soil cutting slope, a self-pressurizing device is designed, which can prevent the attenuation of the expansive soil strength caused by the expansion and contraction cycle under the action of the atmosphere, and maintain the expansive soil strength. So as to ensure the stability of the expansive soil cutting slope and play the role of cutting slope protection. By changing the self-pressurization pressure and influence range, and using different materials, a reliable expansive soil cutting slope protection system can be formed, which is suitable for expansive soil cutting slopes with different expansion and contraction properties.

The present invention combines the evolution process of expansive soil cutting slope catastrophe, adopts a self-pressurizing device, and can also be combined with materials such as bamboo or wood to use self-pressurizing pressure to prevent the strength attenuation caused by the expansion and contraction cycle of expansive soil, thereby maintaining the cut. Slope stability provides theoretical basis and technical support for green protection of cutting slopes in expansive soil areas, and also provides useful reference for special soil slope protection in other areas. The method can reduce the cost of cutting slope protection engineering, is applicable to various soil layers, and has broad engineering application prospects.

Example 1

As shown in Figures 1 and 2, a self-pressurized protective device for maintaining the stability of expansive soil cutting slopes includes anchor rods 1, a first circular plate 2, a second circular plate 3, and a high-strength spring 4. The first The circular plate 2 and the second circular plate 3 are set on the anchor rod 1, a single high-strength spring 4 is arranged between the first circular plate 2 and the second circular plate 3, and the first circular plate 2 is provided with Nut 5, said nut 5 is fixedly sleeved on the anchor rod 1. The diameter of the first circular plate 2 is smaller than the diameter of the second circular plate 3 . The distance between the first circular plate 2 and the second circular plate 3 is 0.2-0.5m.

As shown in Figure 5, the depth of the anchor rod 1 buried in the soil is 1.5-2 times the depth of the severe influence of the atmosphere.

Example 2

As shown in Figures 3 and 4, a self-pressurized protective device for maintaining the stability of expansive soil cutting slopes includes anchor rods 1, a first circular plate 2, a second circular plate 3, and a high-strength spring 4. The first The circular plate 2 and the second circular plate 3 are set on the anchor rod 1, three high-strength springs 4 are arranged between the first circular plate 2 and the second circular plate 3, and the first circular plate 2 is provided with Nut 5, said nut 5 is fixedly sleeved on the anchor rod 1. The diameter of the first circular plate 2 is smaller than the diameter of the second circular plate 3 . The distance between the first circular plate 2 and the second circular plate 3 is 0.2-0.5m.

As shown in Figure 5, the depth of the anchor rod 1 buried in the soil is 1.5-2 times the depth of the severe influence of the atmosphere.

A self-pressurization protection method for maintaining the stability of expansive soil cutting slope, characterized in that the steps include:

Step 1) Sampling on site, carrying out expansion and deformation tests, determining the expansion and deformation of soil samples when the soil sample is covered by 0kPa, 12.5kPa, 25kPa, 50kPa and 100kPa through indoor tests, and converting the upper expansion and deformation when the expansion and deformation are zero by interpolation. Overburden stress δ;

Step 2) through the overlying compressive stress δ, the area A of the second circular plate 3 and the deformation coefficient k of the high-strength spring 4, the deformation amount s=(δ·A)/k of the spring is converted;

Step 3) Judging the depth d of the severe influence of the soil atmosphere on the basis of the building technical specifications in expansive soil areas;

Step 4) According to the depth d of severe atmospheric influence, consider the soil anchorage force F=1.2·δ·A, the strength parameters c, φ of the soil in the test anchorage area, and the friction coefficient μ of the anchor rod 1, and calculate the required value of the anchor rod 1 according to the specification. the length l below the depth of severe atmospheric influence;

Step 5) Determine the total length L of the anchor rod 1 of the self-pressurizing device according to the length l of the anchor rod 1 that needs to penetrate below the depth of the severe atmospheric influence, the depth d of the severe atmospheric influence, the deformation amount s of the high-strength spring 4, and the length m of the self-pressurizing device =l+d+m-s;

Step 6) Hammering in different combinations of self-pressurizing devices, the depth of the anchor 1 into the soil is D=l+d, and the slope layout is shown in Figure 6.

In this device, the high-strength spring 4 between the first circular plate 2 and the second circular plate 3 is deformed by driving the anchor rod 1 into the soil, and generates pressure on the second circular plate 3. The pressure can be controlled by controlling the anchor rod 1. The size of the spring deformation caused by the depth is determined. The pressure is transmitted to the surface of the expansive soil through the second circular plate 3. The applied pressure can limit the expansion and contraction deformation of the expansive soil, maintain the dry density of the soil, and reduce the influence of the atmosphere on the strength of the expansive soil. So as to maintain the stability of expansive soil cutting slope. Using the driving-in method for construction, the pressure exerted by spring compression on the second circular plate 3 can be artificially controlled by the driving amount of the anchor rod 1; the self-pressurizing protection device on the cutting slope can be arranged in the form of plum blossoms.

When the soil tends to be broken and the cracks are relatively developed, it can be considered to use two self-pressurizing devices or a group of three self-pressurizing devices through calculation, as shown in Figure 7, and construct according to the above method.

Atmosphere strongly affects depth:

Atmospheric influence depth is the effective depth of soil deformation caused by rainfall, evaporation, ground temperature and other factors under the action of natural climate. The depth of severe atmospheric influence refers to the depth at which the atmospheric influence is particularly significant, which is basically 0.45 times the depth of atmospheric influence. For details, refer to the technical code for construction in expansive soil areas.

Claims (1)

1. one kind maintains the self-pressurization means of defence that swelled ground moat slope is stable, it is characterised in that step includes:

Step 1) field investigation and sampling, carry out dilatancy test, by laboratory test determine soil sample overlying 0kPa, 12.5kPa, 25 Soil sample dilatancy amount when kPa, 50 kPa and 100 kPa, conversing dilatancy amount by interpolation is overlying pressure when zero Stress δ；

Step 2) self-pressurization preventer, including anchor pole, the first plectane, the second plectane, high strong spring, it is characterised in that described First plectane and the second plectane are enclosed within anchor pole, are provided with high strong spring between the first described plectane and the second plectane, described First plectane is provided with nut, and described nut fixed cover is on anchor pole, by overlying compressive stress δ, the second plectane area A and height The deformation coefficient k of strong spring, converses deflection s=(δ the A)/k of spring；

Step 3) judges soil body air dramatic impact degree of depth d according to Technical code for buildings in swelling soil zone；

Step 4) is according to air dramatic impact degree of depth d, it is considered to soil body anchor force F=1.2 δ A, the test anchorage zone soil body strong Degree parameter c, φ, anchor pole coefficientoffrictionμ, converse anchor pole according to specification and need to be deep into the length of below the air dramatic impact degree of depth l；

Step 5) need to be deep into length l of below the air dramatic impact degree of depth, air dramatic impact degree of depth d, spring according to anchor pole Deflection s and self-pressurization device length m, determine self-pressurization device anchor pole total length L=l+d+m-s；

The mode of step 6) hammering is driven into self-pressurization device, and anchor pole embedded depth is D=l+d.