What happens when clay with high liquid limits is used directly as a filler

High liquid limit clay is used directly as a filler, and if left untreated, the following hazards will occur:

1. Landslides. Because the shoulder is empty, it is susceptible to weathering, frequent expansion and contraction of dry and wet, and the strength of the soil is attenuated, and when rainwater infiltrates, especially when the shoulder produces longitudinal cracks, it is easy to collapse.

2. Cracks appear.

The shoulder part is often not in place because of mechanical rolling, so that the fill can not reach the required compactness, so the settlement in the later stage is relatively large.

3. Sedimentation. The initial structural strength of high-liquid limited soil is high, and it is not easy to be crushed or compacted during construction. After the embankment is filled, due to the physical weathering of the atmosphere and the effect of wet expansion and contraction, the soil block disintegrates, and the embankment is prone to uneven settlement under the action of the upper road surface, the self-weight of the roadbed and the automobile load.

The higher the embankment, the greater the amount of settlement, and the more common the settlement. The uneven settlement leads to the decline of the pavement flatness, and in serious cases, the pavement can be deformed and damaged, and even repeatedly repaired.

The engineering properties of high-liquid confined soil are related to the composition of the parent rock, water content, compactness, external load size and mode of action, and other physical and chemical processes. According to a large number of engineering practices, it can be seen that the permeability of high liquid limited soil is poor; High strength when dry and hard, hard and not easy to excavate, not easy to compact; The capillary phenomenon is obvious, and it can retain water for a long time after water absorption, so the bearing capacity is small and the stability is poor after water absorption; It has large plasticity, weak expansion and viscosity.

Question 1: What is the difference between silty clay with low liquid limit and low liquid limit clay 15 points When the plasticity index ip is greater than 10 and less than 17, it is called low liquid limit silty clay; When the plasticity index IP is greater than 17, it is called a low liquid limit clay.

Question 2: Is it better to have a lower clay limit? Is the higher the plastic limit, the better The boundary water content of the soil from semi-solid to plastic state is called the plastic limit;

The boundary water content from the plastic state to the flow state is called the liquid limit.

Plasticity index = liquid limited water content plastic limited water content;

Liquid rotability index = (natural water content of soil, plastic limited water content) plasticity index.

The smaller the liquid index of the soil, the harder the soil and the better.

Question 3: What is low limit clay? The liquid limit is less than 50% clay.

Question 4: Why is the clay with high liquid limit not suitable for roadbed The clay with high liquid limit has poor water stability, it is easy to expand and soften when exposed to water, and it will dry up and shrink when it loses water, and because of its fine soil particles and large capillary water rising height, it will destroy the stability of the roadbed, so it cannot be directly used for roadbed filler.

Subgrade: Subgrade engineering is a sub-discipline of road and bridge engineering. The content of the subgrade project is to carefully do a good job in the design, construction, monitoring and maintenance management of the subgrade, so as to provide the subgrade structure that meets the performance requirements for the pavement and vehicle driving.

Subgrade Engineering (2nd Edition) is a national planning textbook for general higher education in the "Eleventh Five-Year Plan", which can be used as a teaching book for civil engineering in colleges and universities, and can also be used as a reference for engineering and technical personnel and management personnel engaged in civil engineering.

Question 5: What is high liquid limit clay and high liquid limit silt? Soil with a particle content greater than 50%, a liquid limit greater than 50%, and a plasticity index greater than 26 is called a high liquid limit soil. And what you are talking about in your question is only the clay and silt in the high liquid limit soil.

Question 6: What is the difference between high liquid limit soil and low plastic limit soil The higher the liquid limit of soil, the greater the hardness, and the better the stability.

Question 7: The smaller the clay particles, the lower the liquid limit, is it right or wrong? The clay with high liquid limit has large particles, and the dispersion degree in water is very large, which is not easy to dry, and the strength of the wet billet is also low. And vice versa, so it's right.

A kind of clay, high-limit clay belongs to slope residue from geological origin, lithology is gravel-bearing clay, gravel content is mostly 20% 30%, is the weathering product of volcaniclastic rock, mostly reddish-brown, the maximum thickness is more than 10 m.

The clay has very special physical and mechanical properties, such as average water content of 56%, dry density of 13 6 kN m', wet density of l5 2 kN, liquid limit of 77, plastic limit of 39, unconfined compressive strength of 34 kpa, optimal water content of 38%, maximum dry density of 13 9 kN.

High liquid limited soil, high water content, light bulk density, poor stability, low strength, according to the conventional construction technology compaction can not meet the requirements of the design specification. High liquid limit soil generally refers to soil with a liquid limit greater than 50% and a plasticity index greater than 26.

The plastic limit of clay is collectively referred to as the limit moisture content, we assume that the plastic limit of a clay is 30%, and the liquid limit is 42%, then when the moisture content of the soil sample is less than 30%, the soil is in a semi-solid state, when its value is between 30% and 42%, the soil is in a plastic state, like plasticine, of course, the greater its value, the better the plasticity, and when its value is greater than 42%, the soil will be saturated with water due to excessive water content, and free water appears, so the soil is in a flowing state in the case of too much water.

Generally speaking, the smaller the water content of the soil, the greater the strength, therefore, it can be said that the strength of the clay with a higher plastic limit is less sensitive to water and the engineering properties are good.

High liquid limit clay.

In the project, the three indicators for identifying high liquid limit soil are: less than the particle content is greater than 50%, the liquid limit is greater than 50%, and the plasticity index is greater than 26. In addition to the characteristics of water expansion and water loss contraction, the more important feature is that the compaction of high liquid limited soil is poor, and the compressibility of the soil after compaction is still large, and there is obvious strain softening.

Many slope projects lose their effectiveness because they do not recognize the essential characteristics of high-liquid confined soil.

A kind of clay, high-limit clay belongs to slope residue from geological origin, lithology is gravel-bearing clay, gravel content is mostly 20% 30%, is the weathering product of volcaniclastic rock, mostly reddish-brown, the maximum thickness is more than 10 m.

The clay has very special physical and mechanical properties, such as average water content of 56%, dry density of 13 6 kN m', wet density of l5 2 kN, liquid limit of 77, plastic limit of 39, unconfined compressive strength of 34 kpa, optimal water content of 38%, maximum dry density of 13 9 kN.

High liquid limited soil, high water content, light bulk density, poor stability, low strength, according to the conventional construction technology compaction can not meet the requirements of the design specification. High liquid limit soil generally refers to soil with a liquid limit greater than 50% and a plasticity index greater than 26.

Expand to make hail information:

During the construction of the rainy season, the cross slope of the road arch can be appropriately increased, the cross slope of the edging soil is 1 2% larger than the cross slope of the high liquid limit soil, and the water content of the embankment should be repressed and the degree of compaction should be detected when the water content of the embankment is suitable after the rain, and the road section with the sheep's foot should pay attention to the re-pressure with the smooth wheel roller to eliminate the groove.

During continuous sunny day construction, the lower layer should be covered with the upper layer of earthwork in time after the construction is completed, so as to avoid cracking due to the evaporation of water on the surface of the roadbed caused by exposure, and the cracked should be re-loosened and rolled.

Encyclopedia - High Liquid Limit Clay.

Encyclopedia - High Liquid Limit Soil.