Is digging concrete pavement an extremely soft rock?

No, the extremely soft rock is clay and the like, which can be kneaded into slag by hand after absorbing water, and the softer rock can be kneaded into blocks.

It can be determined according to the saturated uniaxial compressive strength, which is more than 60 MPa for hard rock, between 30 and 60 for harder rock, 15 30 for softer rock, 5 15 for soft rock, and less than 5 for very soft rock.

Soft rock refers to rock with a uniaxial compressive strength of less than 30MPa.

Soft rock is a complex rock mechanical medium with significant plastic deformation in a specific environment, which can be divided into two categories: geological soft rock and engineering soft rock. Geological soft rock refers to the loose, scattered, soft and weak rock layers with low strength, large porosity, poor cementation, significant influence by structural plane cutting and weathering, or containing a large number of expansive clay minerals, and this kind of rock is mostly mudstone, shale, siltstone and argillaceous ore, which is a naturally formed complex geological medium; Engineering soft rock refers to the engineering rock mass that can produce significant plastic deformation under the action of engineering force. Engineering soft rock emphasizes the magnitude of the engineering load borne by the soft rock, and emphasizes the analysis and grasp of the relative essence of the soft rock from the opposition and unity relationship between the strength of the soft rock and the engineering load.

The relationship between engineering soft rock and geological soft rock is as follows: when the strength of the engineering load relative to the geological soft rock (such as shale, etc.) is small enough, the geological soft rock does not produce the significant plastic deformation mechanical characteristics of the soft rock, that is, it is not regarded as engineering soft rock, and only the geological soft rock that has undergone significant deformation under the action of engineering force is regarded as engineering soft rock; Under the action of large depth and high stress, some geological hard rocks (such as argillaceous cemented sandstone, etc.) also show significant deformation characteristics, so they should be regarded as engineering soft rocks.

According to the differences in the characteristics of soft rocks and the mechanism of significant plastic deformation, soft rocks can be divided into four categories, including expansive soft rock, high-stress soft rock, jointed soft rock and composite soft rock.

According to the different types of high stress, high stress soft rock can be subdivided into self-weight stressed soft rock and tectonically stressed soft rock. The former is characterized by being depth-independent and direction-independent; The latter is characterized by having nothing to do with depth, but with direction. Highly stressed soft rock is divided into 3 grades according to the stress level, namely highly stressed soft rock, ultra-high stress soft rock, and very high stress soft rock.

High Stress Soft Rock Grading Grade Stress Level MPA

High Stress Soft Rock 25 50

Ultra-high stress soft rock 50 75

Very High Stress Soft Rock 75

Very soft rocks mainly refer to rocks with a mineral composition dominated by clay, carbonaceous, sericite and hydromica. Its ultimate compressive strength is generally less than 5MPa, and the softening coefficient is greater than that.

There is no such thing as extremely soft rock in the classification of geological rocks, which can be classified as mudstone.

Extremely soft rocks mainly refer to rocks with clay, carbonaceous, sericite and hydromica as the main mineral compositions. Its ultimate compressive strength is generally less than 5MPa, and the soft fighting coefficient is large.

The quota of pipeline earthworks shall be specified as follows for calculating the earthwork grading coefficient of trenching

The "Technical Code for the Construction of Highway Bridges and Culverts" (JTJ041 2000) shows that the slope of the pit wall without supporting the foundation is as follows

1. When excavating pebbles and gravel: there is no load at the top of the slope, and the coefficient is 1:; There is a static load at the top of the slope, and the coefficient is 1:1; There is a dynamic load at the top of the slope with a coefficient of 1:.

2. When excavating extremely soft rock, the grading coefficient:

No load at the top of the slope, 1:

There is a static load at the top of the slope, 1:

There is a dynamic load at the top of the slope, 1:

3. When excavating soft rock, the grading coefficient:

No load at the top of the slope, 1:0

There is a static load at the top of the slope, 1:

There is a dynamic load at the top of the slope, 1:

4. When excavating hard rock, the grading coefficient:

No load at the top of the slope, 1:0

There is a static load at the top of the slope, 1:0

There is a dynamic load at the top of the slope, 1:0

Rocks with a uniaxial saturated compressive strength greater than 60 MPa are called "hard rock", those with 3060 MPa are called "harder rocks", and those with less than 30 MPa are called "soft rocks".

In addition to the compressive strength index of rock, a series of natural factors such as rock genesis, lithology, occurrence, fracture development degree and weathering degree should also be considered.

In the engineering geology research of rocks, due to the poor mechanical strength and solidity of soft rock, it often becomes the focus of engineering geology research in bedrock areas, and hard rock is softer than hard rock.

According to the GB50007-2011 "Code for Design of Building Foundations", the judging criteria are as follows:

In the construction of housing construction projects, the general height is measured in meters, the area is measured in square meters, and the units that are not marked are more than mm, and the latter every 10mm increase means that when doing the project valuation, the cost of each increase of 10mm on the basis of the concrete thickness of 100mm is increased; Just a personal point of view, I hope it helps you;

The statement within the quota, within 100 generally refers to millimeters, for example, if you want to calculate the manual excavation of 100mm thick concrete pavement, set this quota on the line, if it is 110mm, you have to set two quotas, first set within 100 and then set every increase of 10mm, if it is 90mm, first set of 100 and then set every increase of 10mm (negative engineering quantity).

The unit is mm, manual excavation of concrete pavement, pavement thickness within 100 mm, if the excavation exceeds 100 mm, the remaining thickness according to TGD1-003 artificial excavation of concrete pavement, thickness of more than 100 mm, each increase of 10 mm to calculate.

This means that if the concrete pavement is excavated manually, the thickness of the concrete pavement should be controlled within 100mm, and the thickness should not be manually excavated if the thickness exceeds 100mm.

What does it mean to manually excavate concrete pavement (within 100) Is this 100 unit m or mm, and what does it mean to manually excavate concrete pavement (every 10mm increase).

I think 100 square meters should be filled in within 100, and every 10 should be filled.

Quota You have to look at the quota of the place, and the quota is different in different regions.

There are also areas of soft rock, softer rocks are together, not so fine.