*The purpose of the work* . Familiarization with the practical methods of stowage of bulk cargoes (on the example of coal) in the port in compliance with safety regulations and fire prevention measures.

*General instructions* . When storing coal in the port, the most common are stacks in the form of a *wedge* and *an obelisk* . Stacks in the form of a cone, pyramid and prism are much less common and, especially with large cargo flows, are less effective. This is due to the fact that the area allocated for stacks of goods in the form of these figures is much larger (due to passages and driveways) than that of an obelisk or wedge (with the same amount of cargo). *The angle of repose* a of coal in piles depends on many factors and *ranges* from 30 to 45°.

When *placing* coal in warehouses, it is necessary to determine the *length* L _{pcs} , the *width* B _{pcs} and *the height* H _{pcs} of the stack.

*The width* of the stack is determined by the *width of the platform* and the size of the *passages* between the stack and structures (buildings, structures, railway and crane tracks, roads, etc.). The following *minimum* (more is possible, less is not possible) values are determined when placing bulk cargoes:

distance from *the axis* of the railway track to the stack – 2.5 m;

distance from the crane runway ( *rail* head) – 2 m;

passages *between* stacks – 6 m.

Most of the cranes used in the port have a gantry width (the distance between the rail heads of the *crane* tracks) of 10.5 m. The railway tracks in the port have the same width as the entire Ukrainian *railway* network – 1520 mm.

*The height* of the stack is determined by the *restrictions* associated with:

using the *technical norm of the load* on the floor of the warehouse;

*transport characteristics of the* cargo.

*The technical load rate* (P _{t} ) on the *first* site is taken equal to 6 t / m ^{2} , on the *second* – 10 t / m ^{2} . If *one* platform is given, then the load (P _{t} ) on it corresponds to the value *of the first* platform. If *two* sites are given, then it is better to place *anthracite* on the *second* one.

For *coal,* the main height limitation is determined by transport characteristics, namely the tendency to *spontaneous combustion* . According to the terms of *fire* safety, depending on the *brand of* coal and the *shelf* life, the permissible heights of its stacking are determined (MOPOG Rules).

In this *paper* , we assume that the height of coal storage according to transport characteristics:

anthracite (grades starting with the letter A) – not limited;

coal grade PZH, PS – 3 m;

coal grades T, G, D – 2 m.

The spatial arrangement of structural elements on the sites is as follows:

if *one* site is specified, it is located between the railway and crane tracks (Fig. 30);

Rice. 30. Layout of stacks on one site

if *two* sites are given, they are separated by a crane runway and limited by railway tracks (Fig. 31).

Rice. 31. Layout of stacks on two sites

*The length* of the stack is determined by the *width* and *height of* the stack, its *shape* and *the size of the batch of* cargo to be stacked.

*Work order* . In accordance with the given *option* , we determine:

brand and quantity (Q _{pcs} ) of each type of coal, t;

number and width (in _{pl} ) of the site (sites), m:

bulk weight of cargo g, t / m ^{3} .

Since it is necessary to determine the linear dimensions of the stack, then first, by the amount of cargo for *each brand of* coal, we determine *the volume of the* corresponding stacks, m ^{3} :

V _{pcs} = Q _{pcs} / g.

According to the assignment, the width of the *two* sites is the *same* (if two are specified), therefore, having calculated the *width of the stack* on *one* site, we automatically obtain the width of the stack on the *second* .

*The width of the stack* , V _{pcs,} is calculated as *the difference between the* width of the platform, V _{pl} , and the distances from the railway and crane tracks.

Since the minimum distance from the *head* of the rail of the *crane runway* is 2 m, and from *the axis of the railway* track is 2.5 m, then B _{pcs} is determined from the following expression, m:

In _{pcs} u003d In _{pl} – 2.0 – (2.5 – 1.52 / 2).

For coal grades PZh, PS, T, G, D, the possible *height* of stacking (H¢) is *set* , and for *anthracites* (grade A) it is necessary to *determine* this *height* , m:

H¢ = P _{t} / g.

For *each brand of* coal, we calculate the *tangent* of the possible angle of dumping of cargo, subject to the required heights of the stacks:

tga = H¢ / (1/2 × H _{pcs} ).

For a stack *of each brand of* coal, *one* of *three* situations is possible:

1. If tga < 0.5774 (a < 30°), then placing the load in a stack in the form of a wedge (Fig. 32, a - line 1) *is not possible* , since a cannot be *less than* 30°. This *can be* only if the stack is specially *leveled* to reduce the angle, but *in practice* this is *not applied* . Then the necessary *data for calculating* the stack length (L) are as follows:

a *u003d* 30 ° (we increase to the *minimum* possible);

stack shape – *obelisk* (Fig. 3, a – line 2);

H=H¢; V _{about} u003d V _{pcs} ; B = B _{pcs} ;

*calculate* the side of the base A:

A = 2 × H¢/ tga.

2. If 0.5774 < tga < 1.0 (30° < a < 45°), then the required *data for calculating* the stack length (L) are as follows:

a – *equal* to the *calculated* value;

stack shape – *wedge* ;

H=H¢; V _{cl} u003d V _{pcs} ; B = In _{pcs} .

Rice. 32. Determining the shape of the stack

3. If tgau003e 1.0 (au003e 45 °), and this is *not possible* , since a cannot be *more than* 45 ° (Fig. 32, b – line 1). *Theoretically* , with the help of various expensive methods, it is *possible to* increase a, but *in practice* this is *not applied* . With the height of the dumping H¢ and the actual value a, the stack width B _{pcs} will be greater than the calculated one. In this case, the necessary *distances* from the rail heads to the stack *will not be* observed, and it is generally possible to *fill the rails* with cargo, which is *unacceptable* . Then the necessary *data for calculating* the stack length (L) are as follows:

a *u003d* 45 ° (we lower it to the *maximum* possible);

stack shape – *wedge* (Fig. 32, b – line 2);

V _{cl} u003d V _{pcs} ; B = B _{pcs} ;

recalculate the height H downward:

H = B _{pcs} × tga / 2.

To *determine the length of* stacks L, the calculation formulas for determining the volumes of stacks in the form of a *wedge* and *an obelisk* are used (see lab. work. 5). *Having carried* out simple *transformations* of the calculation formulas, we obtain:

for a *wedge* : L u003d (V _{cl} + 1/3 × H × B ^{2} ) / (1/2 × B × H);

for *an obelisk* : L u003d (V _{about} + 1/2 × A × B × H – 1/3 × H × A ^{2} ) / (B × H – 1/2 × A × H).

At the end of the work, a *diagram of the placement of* stacks in the warehouse is given, indicating the *paths* , *driveways* , *aisles* and all *sizes* (Fig. 30 and 31).

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