Environmental Engineering Reference
In-Depth Information
2.4.7
Data Presentation
Basic Elements
Location Plan
Locations of all explorations should be shown accurately on a plan. It is helpful to use
a topographic map as a base map, which also shows the surficial geology as in
Figure
2.88.
A map providing the general site location is also useful, especially for future refer-
ence to local geologic conditions. Many reports lack an accurate description of the site
location.
Geologic Sections
Data from the various exploration methods are used as a basis for typical geologic sec-
tions to illustrate the more significant geologic conditions, as in
Figure 2.89.
The objective
is to illustrate clearly the problems of the geologic environment influencing design and
construction.
For engineering evaluations, it is often useful to prepare large-scale sections on which
are plotted all of the key engineering property data as measured in the field and in the lab-
oratory.
Fence diagrams, or three-dimensional sections, are helpful for sites with complex geol-
ogy. An example is given in
Figure 2.90.
Logs
The results of test and core borings, test pits, and other reconnaissance methods are pre-
sented on logs which include all pertinent information.
6
34
7
45
46
21
20
27
+15
+15
+10
+10
21
17
50
Final
grade
12
20
22
25
14
13
7
11
12
12
7
12
13
20
20
21
16
27
10
4
16
15
24
20
30
22
23
19
14
11
13
15
22
18
21
22
16
26
32
+5
+5
14
27
28
24
16
6
6
12
12
6
13
8
10
10
11
18
27
11
20
15
18
10
6
10
8
4
6
7
13
26
20
12
23
19
26
14
23
32
50
0
0
0
1
4
4
9
22
2.
4
3
2
2
8
12
15
18
20
12
21
29
22
30
50
50
50
0
1
0
0
0
1.
Soft
2.
3
5
9
−
5
−
5
1.
3.
Firm
3.
−
10
−
10
−
15
−
15
Key to boring
GWL
Numbers to the right of boring indicate
number of blows required by a 65-kg hammer
falling 75 m to drive a 5-cm O.D. sampling spoon to
30 cm (Approximately equivalent to understand
penetration resistance.)
28
22
9
5
−
20
−
20
Horizontal scale (m)
0 0 0 0
Section A-A
FIGURE 2.89
Typical geologic section across site shown in stratum descriptions in
Figure 2.88:
(1) recent alluvium marine
deposits consisting of interbedded organic silts, sands, and clays; (2) residual soil: silt, clay, and sand mixtures;
(3) micaceous saprolite: highly decomposed gneiss retaining relict structure; (4) weathered and partially
decomposed gneiss. (Courtesy of Joseph S. Ward and Assoc.)
