JPS5840612B2 - Excavated soil improvement method - Google Patents

Description

[Detailed description of the invention] This invention relates to a method for improving the quality of excavated soil.

In the conventional excavated soil improvement method, as shown in Figure 1, the excavated soil is
First, the material is crushed by a plurality of crushers 2 installed on the raw material receiving hopper 3 and sieved by a primary sieve 1 such as a movable grizzly, and coarse foreign matter in the excavated soil, for example, 150 square meters or more, is removed by a foreign matter conveyor 8 to the outside. The excavated soil is then supplied to the raw material receiving hopper 3 as excavated soil to be improved.

When this raw material excavated soil is sent from the raw material hopper to the raw material conveyor 7 by the belt feeder 4, it is further crushed by a plurality of crushers 5.

The reason why the plurality of crushers 5 are provided in multiple stages in the height direction is that in the case of highly sticky excavated soil, it may not be possible to feed it smoothly to the raw material conveyor 7 with the belt feeder 4 alone. 4. This is to allow the material excavated soil that has piled up on top to be sent out while being crushed.

Also, the flat conveyor 6 below this belt feeder 4
is for collecting the excavated soil that has fallen onto the belt feeder 4 and sending it to the raw material conveyor 7.

Next, the raw material excavated soil is conveyed to a secondary sieve 9 such as a screen by the raw material conveyor 7, and the foreign matter on the top is removed to the outside by the foreign matter conveyor 10, for example, 50 mm JJ.

The raw material excavated soil that has passed through the secondary sieve 9 is removed by an excess soil remover 12 provided on a belt feeder 11 to form a layer with a constant thickness.

The surplus soil that has been removed is recycled to the belt feeder 11 by the surplus soil conveyor 13.

A soil conditioner is added at a predetermined ratio to this raw material excavated soil with a constant layer thickness by a quantitative feeder 14, and a belt feeder 1
The improved soil is crushed and mixed by a crusher 19 installed at the end of the soil.

In this case, some of the scattered soil conditioner is collected by the dust collector 18 and returned to the supply device 14.

Next, the improved soil is supplied by a conveyor 20 to a mixer 21 such as a pug mill, where it is further crushed and mixed to become complete improved soil, and then transferred to a conveyor 22 to switch to a mixer 23.
The material is then transported to a storage location by the transport conveyor 24, and then loaded onto a truck and transported to the backfilling site.

By the way, in the case of highly sticky excavated soil, the raw excavated soil adheres to the raw material conveyor 7 and falls and accumulates under the conveyor 7, so it takes a lot of effort to dispose of the deposits, and it also takes a lot of time to scrape.
- It adheres to the secondary sieve 9, such as a sieve, and causes clogging, reducing the passage rate of the screen.

If the stickiness is high, there are problems such as the soil conditioner not being mixed uniformly.

These phenomena reduce the efficiency of the plant and are also unfavorable from the standpoint of the quality of the improved soil.

This invention was made to solve the above-mentioned problems, and its purpose is to improve the processing efficiency of highly sticky excavated soil and to improve the quality of improved soil. The purpose is to provide an improved method.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

The same reference numerals are used for the same parts as in FIG. 1 of the conventional button method, and a description thereof will be omitted.

A is the excavated soil to be improved after passing through a primary sieve 1 such as a movable grizzly to remove coarse foreign matter.

15 is the primary fixed quantity supply device for soil conditioner; conditioner hopper 1;
5a and a quantitative feeder 15b such as a rotary feeder.

Here, 1 part b1 of the improvement agent to be added at a predetermined ratio to the amount of excavated soil a to be treated is added from the quantitative feeder 15b, and primary crushing and mixing is performed by the crusher 5. Next, the excavated soil is treated as a1.

The soil conditioner is a mixture of limestone powder, cement, granulated slag, etc., and by adding and mixing this, the stickiness of the excavated soil a is reduced.

The excavated soil a1 that has been subjected to the primary treatment in this way is transferred to the raw material conveyor 7.
is transported to the secondary sieve 9.

As shown in FIGS. 3 and 4, the excavated soil a1 that has passed through the secondary sieve 9 is placed on a belt feeder 11, and the surplus soil is removed by the surplus soil remover 12 to form a layer with a constant thickness.

Reference numeral 16 denotes a secondary metering supply device for the soil conditioner, which is comprised of a conditioner hopper 16a and a metering feeder 16b such as a rotary feeder.

The remainder b2 of the improving agent to be added to the treated excavated soil a1, which has a constant layer thickness, is added from the quantitative feeder 16b, and the crusher 19 performs secondary crushing and mixing to improve the improved soil C.
That's what I say.

This improved soil C is supplied to a mixer 21 such as a pug mill by a conveyor 20 shown in FIG. 1, where it is further thoroughly crushed and mixed.

Dust collector for recycling surplus soil and soil conditioner 18
Recovery, etc. will be carried out in the same manner as before.

Next, specific examples of the method of this invention will be described.

A case in which 1.2 tons of soil conditioner was added to 15 tons of sticky excavated soil to improve the soil quality using the quantitative feeder 14 using the conventional method, and a case in which 1.2 tons of soil conditioner was added using the method of the present invention using the primary quantitative feeder. When adding 10.4t of the first part of 10.4t to the second quantitative feeder 16 and the remaining part of 20°8t using the secondary quantitative feeder 16, 15.5t of finished soil was added to the finished soil, compared to 14.5t of the conventional method.
The yield is 95.3 and 6.5t from 88°6q6.
7 ratio has been improved, and the loss due to a decrease in the passing rate of the secondary sieve 9 and falling from the raw material conveyor 7 has been significantly reduced from 1.7 t to 0.7 t.

As explained above, the following effects can be obtained by the method of the present invention, in which the soil conditioner is added and mixed to sticky excavated soil in two stages, one after the first stage and the other after the second stage.

(1) By reducing the stickiness of the excavated soil whose soil quality should be improved after the first stage, the passing rate of the secondary sieve decreases and losses due to falling from the raw material conveyor are reduced, improving yield and processing efficiency. do.

Moreover, the cost of processing the deposits that fall and accumulate from the raw material conveyor can be reduced.

(2) By reducing the stickiness of the excavated soil and adding and mixing the soil conditioner in portions, the mixture of the conditioner becomes uniform and the quality of the improved soil improves.

[Brief explanation of the drawing]

Figure 1 is a flow sheet diagram of the conventional excavated soil improvement method, Figure 2
The figure is a vertical cross-sectional view of the area around the primary metered supply device for a soil conditioner that implements the method of the present invention, and Figures 3 and 4 show the area around the secondary metered feed device for the soil conditioner that implements the method of this invention. They are a plan view and a longitudinal cross-sectional view. 1... Primary sieve, a... Excavated soil to be improved, bl
... 1 part of soil conditioner, b2... soil conditioner/remainder, 9... secondary sieve, 19... crusher.

Claims (1)

[Claims] After passing through the 11th sieve to remove coarse foreign matter, 1 part of the soil conditioner is added to the excavated soil to be soil conditioned for primary mixing, and then this is conveyed to the 2nd sieve and disassembled through the 2nd sieve. An excavated soil improvement method characterized by adding the remainder of a soil conditioner between crushers and performing secondary mixing.