Shear Wave Velocity (Vs) and SPT Resistance (N) Correlation for the Isfahan Metro, Iran

doi:10.21203/rs.3.rs-2988422/v1

The evaluation of earthquake damage is a crucial problem for ground improvement, and it is dependent on the ground motion. The shear wave velocity determines the features of an earthquake motion at a location (V_s). Although the shear wave velocity profile at a location might not be easily accessible, the number of blows (N) from a standard penetration test (SPT) is. The establishment of a trustworthy connection between Vs, as determined by multichannel analysis of surface wave testing, and N, as determined by SPT at Isfahan Metro Line 2, is presented in this study. These tests have been run on a total of 22 boring logs (within a radius of 30 km). The index qualities of the SPT samples are examined in a lab setting. The study is crucial for this area since the resistance of the subway structure must be examined. An empirical correlation between V_s and N was created based on the statistical analyses. All soil types, sands only, and clay alone are treated individually in this manner. The established ties are comparable to those established for other sites around the world. Also, a comparison with relevant relations is provided. Given that ground motion is one of the key characteristics in seismic microzonation of the area, the proposed relations will be useful.

shear wave velocity

SPT Resistance

Isfahan Metro

MASW

Standard penetration test

Correlations

The existence of soil deposits at a place has a big impact on the features of an earthquake motion. Either a comprehensive site-specific ground response study is performed, or a simpler site categorization approach is used to analyze the ground motion characteristics. Shear wave velocity (V_s), which reflects the stiffness of the soil layers, is the most significant parameter for all of these techniques. Typically, wave propagation experiments are used to determine the shear wave velocity profile at a place. However, doing these checks at every site is frequently not economically viable. Yet, many sites where geotechnical investigations are conducted have publicly accessible numbers of blows (N) from standard penetration tests (SPT). According to this perspective, a strong empirical connection between V_s and N would be very beneficial. The coordinates of Isfahan are 32.65246 latitude and 51.67462 longitude. Its average elevation is, 1575 m, making it a part of both Asia and the Northern Hemisphere.

The Zagros Mountains, which are mostly sedimentary, reach northwest to southeast from this province. In Fig. 1. Geographically, the province of Isfahan has broad sequences of igneous, metamorphic, and sedimentary rocks of various ages. The Precambrian-Paleozoic metamorphic rocks are mostly found in the province's eastern sections, where they may also be found in deposits from the Mesozoic and Cenozoic eras. The northwest-southeast trending Urmia-girl magmatic belt travels across the province's center (Fig. 2; Table 1). Isfahan Province is a region having structural zones of Central Iran, Orumieh-Dokhtar, Sanandaj-Sirjan, and portions of the Zagros mountains that stretches from east to west. It is possible to identify magmatic arcs up to oceanic pits.

Figure 1 Isfahan topographical picture map

Table 1

Geological structures of the region, as seen in Fig. 3
GEO-UNIT	DESCRIPTION	AGE
Klsol	Grey thick - bedded to massive orbitolina limestone	Early.Cretaceous
Qcf	Clay flat	Quaternary
Qft2	Low level piedment fan and vally terrace deposits	Quaternary
TRJs	Dark grey shale and sandstone (SHEMSHAK FM.)	Triassic-Jurassic
TRn	Sandstone, quartz arenite, shale and fossiliferous limestone (NAIBAND FOR)	Mesozoic

In this study, an attempt has been made to develop a reliable correlation between V_s and N for soils of Isfahan Metro Line 2. The shear wave velocity has been measured by multichannel analysis of surface wave (MASW) tests and SPTs are carried out at 22 boring logs within a radius of 30 km from Isfahan Metro Line 2. The correlation between V_s and N developed for the study area is compared with the existing correlation in the literature.

Correlating the values of V_s with known soil factors, such as N value, has been the subject of several attempts worldwide. Boominathan et al. [5] used the correlations provided by JRA [7] and data on the soil's N value for Chennai, India, to calculate the V_s. Sitharam and Anbazhagan [1] conducted a MASW survey for roughly 38 sites in Bangalore, India, that were close to the locations of the available SPT boreholes. These results were utilized to create a connection between the shear wave velocity and the corrected N values. Hanumantharao and Ramana [26] determined correlations between V_s and N value for Delhi city, India, by measuring shear wave velocity using SASW at 80 places to a depth of 20–32 m.

Several researchers in Japan established relationships between V_s and N while taking the geological age and soil type into account [20 − 8]. For Tehran, Jafari et al. [2] have presented connections. Similar investigations were conducted in the USA and Taiwan, where uncorrected N values were used to construct correlations between V_s and N [13, 20]. The literature does not, however, include the correlation of V_s- N for the Isfahan Metro Line 2. The Vs- N relationship for a total of 22 boring logs in the Isfahan Metro Line 2 has been explored in the current work. In order to do this, MASW experiments were used to investigate the shear wave velocity, and SPTs were used to calculate N values. Based on the results of these experiments, an empirical relation (V_s- N) that applies to all 22 boring logs was examined. Three different types of soil deposits—all sorts of soils, sandy soils, and clayey soils—are dealt with independently in this process.

Standard penetration tests (SPT) in accordance with IS 2131 [20] and laboratory analyses of the samples taken from all 22 boring logs were used in the geotechnical studies. Figure 3 depicts the positions of each of the 22 boring logs, while Table 2 provides information on each of the 22 boring logs. Using the SPTs, soil samples were taken from various depths at the 22 boring logs. All of the samples were put through laboratory testing to determine their index characteristics, including grain size distribution [12], specific gravity [14], maximum and minimum void ratio, coefficient of uniformity, coefficient of curvature, dry unit weight, and relative density [18]. For example, for BH-S01 borehole, total 5 samples were collected from different depths using SPT. To learn about their index qualities, all of these samples were evaluated.

Table 3 lists the 22 boring logs' soil types, ranges of N, and ranges of V_s. Table 3 shows that the greatest depth of the drilling is 39 m. N has a range of (1–27) and V_s has a range of (159–910 m/s).

For all 22 boring logs, the change of N values with depth is shown in Fig. 4. These soil profiles show that the BH- S12 and BH- S22 boreholes are the strongest.

Table 2

lists the locations.
S. No.	Name	X	Y	Z	Number of samples
1	BH-S01	551103.498600	3615765.433000	1592.127100	11
2	BH-S02	552821.869100	3616167.831000	1588.339500	13
3	BH-S03	554018.043400	3615946.943000	1585.416400	12
4	BH-S04	555173.236300	3615795.197000	1583.946000	12
5	BH-S05	556373.633300	3615680.414000	1581.252300	13
6	BH-S06	557432.042900	3614831.488000	1581.554200	12
7	BH-S07	558573.818800	3614226.236000	1580.327500	13
8	BH-S08	559918.760700	3613926.309000	1579.155000	13
9	BH-S10A	560370.160800	3613777.782000	1578.994000	13
10	BH-S09	561062.568500	3613726.107000	1577.369700	13
11	BH-S10	561876.689700	3613659.716000	1576.700000	12
12	BH-S11A	562664.440200	3613623.378000	1574.390000	11
13	BH-S11	563674.686100	3613688.673000	1571.331100	13
14	BH-S12	564213.730700	3614099.913000	1570.719200	13
15	BH-S13	564370.693300	3614536.779000	1570.380000	13
16	BH-S21	564410.442800	3615304.690000	1568.698200	13
17	BH-S22	564504.754700	3615861.224000	1565.593600	13
18	BH-38	565364.906600	3617091.958000	1566.982300	13
19	BH-39	566102.922600	3617800.305000	1564.856400	13
20	BH-S25	567613.098600	3619136.534000	1560.831900	13
21	BH-43	568108.295500	3619560.160000	1559.269500	12
22	BH-S26	568812.205600	3621021.085000	1555.774900	13

Table 3

For each of the 22 boring logs, the type of soil, the range of N, and the range of V_s
Test No.	Borehole No.	Depth (m)	USCS	Remark
1	BH-S01	0–1.60	CL – ML	N (5–22) V_s (337–864)
2	BH-S01	1.60–9.40	CL
3	BH-S01	9.40–12.80	CL – ML
4	BH-S01	12.80–15	CL
5	BH-S01	15–20.40	CL – ML
6	BH-S01	20.40–28.40	MH
7	BH-S01	28.40–31.80	SM
8	BH-S01	31.80–34.80	CH
9	BH-S01	34.40–40	MH
10	BH-S02	0–3	CL	N (3–19) V_s (262–833)
11	BH-S02	3–7	CL – ML
12	BH-S02	7–20	CL
13	BH-S02	20–22	SC
14	BH-S02	22–24	GC
15	BH-S02	24–35	CH
16	BH-S02	35–38	MH
17	BH-S02	38–40	CL
18	BH-S03	0–1.20	Man Made Fill	N (3–20) V_s (272–796)
19	BH-S03	1.20–25.20	CL
20	BH-S03	25.20–26.40	CL – ML
21	BH-S03	26.40–39	CL
22	BH-S03	39–40	CH
23	BH-S04	0–3	Man Made Fill	N (3–13) V_s (234–648)
24	BH-S04	3–5	CL
25	BH-S04	5–6.60	CH
26	BH-S04	6.60–8.20	CL – ML
27	BH-S04	8.20–23.70	CL
28	BH-S04	23.70–24.30	SM
29	BH-S04	24.30–30	CL
30	BH-S04	30–33	CH
31	BH-S04	33–40	CL
32	BH-S05	0–1.50	Man Made Fill	N (2–21) V_s (220–826)
33	BH-S05	1.50–5.20	CL
34	BH-S05	5.20–6	CL – ML
35	BH-S05	6–9.50	CL
36	BH-S05	9.50–10.20	ML
37	BH-S05	10.20–12	CL
38	BH-S05	12–15	CH
39	BH-S05	15–22	CL
40	BH-S05	22–25	SC
41	BH-S05	25–26	GM
42	BH-S05	26–30	CL
43	BH-S05	30–33	CH
44	BH-S05	33–40	CL
45	BH-S06	0–0.40	Man Made Fill	N (8–21) V_s (462–808)
46	BH-S06	0.40–11.20	CL
47	BH-S06	11.20–15	GM
48	BH-S06	15–16.50	CL
49	BH-S06	16.50–18	GC
50	BH-S06	18–21	CL
51	BH-S06	21–24	GC
52	BH-S06	24–27	CL
53	BH-S06	27–30	SC
54	BH-S06	30–40	CL
55	BH-S07	0–2.20	Man Made Fill	N (4–14) V_s (277–671)
56	BH-S07	2.20–12	CL
57	BH-S07	12–12.50	CL – ML
58	BH-S07	12.50–15.10	SM
59	BH-S07	15.10–18.05	GM
60	BH-S07	18.05–19.20	GP – GC
61	BH-S07	19.20–20.40	SM
62	BH-S07	20.40–20.80	CL
63	BH-S07	20.80–22.50	GW
64	BH-S07	22.50–25	CL
65	BH-S07	25–26.20	SM
66	BH-S07	26.20–33.50	GP – GM
67	BH-S07	33.50–35	ML
68	BH-S07	35–36	SC
69	BH-S07	36–39	CL
70	BH-S07	39–40	MH
71	BH-S08	0–14.50	CL	N (2–22) V_s (226–839)
72	BH-S08	14.50–15	SC
73	BH-S08	15–18.50	GM
74	BH-S08	18.50–19.60	CL – ML
75	BH-S08	19.60–27	GW
76	BH-S08	27–32	SM
77	BH-S08	32–36.50	ML
78	BH-S08	36.50–37.20	SM
79	BH-S08	37.20–39	CL
80	BH-S08	39–40	CH
81	BH-S10A	0–0.40	Man Made Fill	N (1–21) V_s (174–843)
82	BH-S10A	0.40–3	ML
83	BH-S10A	3–17.60	CL
84	BH-S10A	17.60–18.60	SM
85	BH-S10A	18.60–22.80	GC – GM
86	BH-S10A	22.80–27.50	GM
87	BH-S10A	27.50–30	SM
88	BH-S10A	30–34	SC
89	BH-S10A	34–40	CL
90	BH-S09	0–0.80	Man Made Fill	N (6–21) V_s (377–838)
91	BH-S09	0.80–14	CL
92	BH-S09	14–26	SM
93	BH-S09	26–30	GM
94	BH-S09	30–40	CL
95	BH-S10	0–5.70	CL	N (2–21) V_s (211–883)
96	BH-S10	5.70–6.80	SM
97	BH-S10	6.80–13	CL
98	BH-S10	13–23.20	SM
99	BH-S10	23.20–26.50	CL
100	BH-S10	26.50–27.40	SM
101	BH-S10	27.40–33	CH
102	BH-S10	33–37	ML
103	BH-S10	37–40	CL
104	BH-S11A	0–3	Man Made Fill	N (4–27) V_s (318–979)
105	BH-S11A	3–4	CH
106	BH-S11A	4–9.40	CL
107	BH-S11A	9.40–11.70	SC
108	BH-S11A	11.70–16	SP – SM
109	BH-S11A	16–16.30	CL
110	BH-S11A	16.30–21	SW – SM
111	BH-S11A	21–30.50	SM
112	BH-S11A	30.50–35	CL
113	BH-S11A	35–40	GC
114	BH-S11	0–2.50	Man Made Fill	N (3–18) V_s (281–769)
115	BH-S11	2.50–7	CL
116	BH-S11	7–12	SP
117	BH-S11	12–12.50	SC
118	BH-S11	12.50–18	GP – GM
119	BH-S11	18–21	GW
120	BH-S11	21–25.60	GP – GM
121	BH-S11	25.60–28	SP
122	BH-S11	28–30.50	CL
123	BH-S11	30.50–40	CH
124	BH-S12	0–3	Man Made Fill	N (6–25) V_s (398–913)
125	BH-S12	3–7.80	CH
126	BH-S12	7.80–12	SM
127	BH-S12	12–18	GM
128	BH-S12	18–21	SM
129	BH-S12	21–30/40	GM
130	BH-S12	30/40–40	CL
131	BH-S13	0–2.40	Man Made Fill	N (1–26) V_s (152–910)
132	BH-S13	2.40–7	CH
133	BH-S13	7–8.50	CL
134	BH-S13	8.50–12.20	SW – SM
135	BH-S13	12.20–14	GC
136	BH-S13	14–16	GP – GM
137	BH-S13	16–17	CL
138	BH-S13	17–25	GW – GM
139	BH-S13	25–31	SP – SM
140	BH-S13	31–40	CL
141	BH-S21	0–5	Man Made Fill	N (2–24) V_s (218–899)
142	BH-S21	5–15	SC
143	BH-S21	15–18	SM
144	BH-S21	18–24	GM
145	BH-S21	24–31	SM
146	BH-S21	31–33	GM
147	BH-S21	33–36.70	SP - SC
148	BH-S21	36.70–40	CH
149	BH-S22	0–0.40	Man Made Fill	N (6–26) V_s (380–935)
150	BH-S22	0.40–6	CL
151	BH-S22	6–7	ML
152	BH-S22	7–10	CL
153	BH-S22	10–11.20	SM
154	BH-S22	11.20–15	GM
155	BH-S22	15–17	SM
156	BH-S22	17–24	GM
157	BH-S22	24–30	SM
158	BH-S22	30–40	CL
159	BH-38	0–5.40	Man Made Fill	N (6–19) V_s (392–786)
160	BH-38	5.40–10.40	CL
161	BH-38	10.40–13.20	SC
162	BH-38	13.20–15.40	CH
163	BH-38	15.40–21.70	SM
164	BH-38	21.70–23.50	ML
165	BH-38	23.50–27	CL – ML
166	BH-38	27–29	SM
167	BH-38	29–33	SC
168	BH-38	33–36	CH
169	BH-38	36–40	MH
170	BH-39	0–3.60	Man Made Fill	N (3–23) V_s (266–880)
171	BH-39	3.60–5	CH
172	BH-39	5–15	CL
173	BH-39	15–21	SC
174	BH-39	21–21.50	SM
175	BH-39	21.50–24	CL
176	BH-39	24–30	SM
177	BH-39	30–32	SP – SC
178	BH-39	32–36.70	CH
179	BH-39	36.70–40	CL
180	BH-S25	0–3.80	Man Made Fill	N (1–23) V_s (159–859)
181	BH-S25	3.80–7.50	ML
182	BH-S25	7.50–12.50	CL
183	BH-S25	12.50–18	SW – SM
184	BH-S25	18–24	CL
185	BH-S25	24–29	GC – GM
186	BH-S25	29–34	GP – GM
187	BH-S25	34–38.40	CL
188	BH-S25	38.40–40	CH
189	BH-43	0–1	Man Made Fill	N (1–24) V_s (150–954)
190	BH-43	1–6	CL
191	BH-43	6–12.50	GM
192	BH-43	12.50–14	CL
193	BH-43	14–17	GM
194	BH-43	17–26	SM
195	BH-43	26–40	CL
196	BH-S26	0–8.20	CL	N (1–21) V_s (156–824)
197	BH-S26	8.20–18	SM
198	BH-S26	18–21	SP – SM
199	BH-S26	21–27	SM
200	BH-S26	27–33.40	GM
201	BH-S26	33.40–40	CL

Geophysical Investigation

SPT has historically been used often by geotechnical engineers to gauge the strength of the soil. The shear-wave velocity with depth may be directly measured using the down hole or cross hole profiling methods. Due to the need for boreholes, however, the performance of these approaches for site characterization in urban settings can be very challenging and expensive [16, 8]. Non-invasive seismic exploration has become a potential option to determine the shear wave profiles and resonance frequencies in order to get around these issues. The data collecting procedure used in these seismic studies is rather quick and affordable, and it may be used in cities with little trouble. The 1-D velocity model of each Borehole was obtained in the current study using MASW testing.

On the Isfahan Metro Line 2's 22 drilling logs, the MASW measurements were taken. In order to perform the survey, a linear array of geophones with a maximum frequency of 2 Hz that were spaced apart by 2 m and coupled to a multichannel recorder were used. A 300 mm x 9 300 mm x 25 mm thick metal plate was put at one end of the geophone line, and was struck with a sledge hammer (10 kg) and an elastometer-aided weight drop hammer (EAWDH) of 60 kg as the active sources. Software called SurfSeis 2.0 was used to process the data [21].

Figure 5 displays how the shear wave velocity (V_s) varies with depth for all 22 boring logs. Nevertheless, at all of these sites, higher depth V_s from MASW testing were available. Results are only displayed in Fig. 5 up to the depth for which N values are available (Fig. 4). Figure 5 shows that there is much of a difference in V_s with depth. As a result, findings from MASW tests and those from SPTs are highly correlated.

Empirical Connection for Vs-N Suggested

In the literature, there are several empirical relationships for shear wave velocity (V_s) and penetration resistance (N) for various soils, as shown in Table 4. These relationships all use uncorrected V_s and uncorrected N value as their foundation. All of the relationships shown in Table 4 may be seen to be in the format shown below.

${V_s}=a \times {N^{b\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)$

Where a and b are coefficients that vary depending on the soil type and location. Because the results utilizing these are in good accord with the body of previous research, as shown in the following section, uncorrected values for both V_s and N have also been utilized in the current investigation. Moreover, the suggested connections from the current study are maintained in the same style as Eq. 1.

All Soils

107 data pairs (V_s and N) were used in this study's evaluations. A straightforward regression analysis was used to create the relationships. New connections between Vs (m/s) and N values were proposed as a result of the investigations. Prior to this, the impact of adjustment on N values was studied.

In order to compare the findings of the current investigation with the equations suggested by five other researchers, namely Hanumantharao and Ramana [26], Ohba and Toriumi [20], Imai [11], Jafari et al. [2], and Athanasopoulos [3], data from the present study was compared (Fig. 6). Figure 7 illustrates this contrast when V_s and N for all soils are utilized in the current study and a relationship is established, with the following proposed relationship between V_s (m/s) and N levels for all soil types. R² = 0.9931 is the correlation coefficient for this relationship.

${V_s}=141.84{N^{0.5853\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)$

Table 4

shows some current Vs and N relationships.
Author(s)	V_s (m/s)
Author(s)	All soils	Sands	Clays
Hanumantharao and Ramana [26]	V_s = 82.6N^0.430	V_s = 79.0N^0.434	-
Maheshwari et al. [17]	-	V_s = 95N^0.300	-
Ohba and Toriumi [20]	V_s = 84N^0.310	-	-
Imai [11]	V_s = 91N^0.340	V_s = 80.6N^0.331	V_s = 80.2N^0.292
Ohta and Goto [6]	V_s = 85.35N^0.348	V_s = 88.0N^0.340	-
Jafari et al. [2]	V_s = 121.0N^0.270	V_s = 80.0N^0.330	V_s = 100.0N^0.330
Seed and Idriss [24]	V_s = 61N^0.500	-	-
Lee [13]	-	V_s = 57.4N^0.490	V_s = 114.4N^0.310
Sykora and Stokoe [23]	-	V_s = 100.5N^0.290	-
Okamoto et al. [19]	-	V_s = 125.0N^0.300	-
Pitilakis et al. [9]	-	V_s = 162.0N^0.170	V_s = 165.7N^0.190
Athanasopoulos [3]	V_s = 107.6N^0.360	-	-
Raptakis et al. [22]	-	V_s = 123.4N^0.290	V_s = 184.2N^0.170
Hasancebi and Ulusay [10]	V_s = 90N^0.309	V_s = 90.8N^0.319	V_s =97.9N^0.269
Uma Maheswari et al. [25]	V_s = 95.64N^0.301	V_s = 100.53N^0.265	V_s = 89.31N^0.358
Esfehanizadeh et al. [15]	-	V_s = 107.2N^0.34	-
Fatehnia et al. [4]	-	V_s = 77.1N^0.355	V_s = 77.1N^0.355

Sandy Soils

Similar to other soil types, sand-based soils also underwent regression analysis; out of 107 data pairings, 30 related to sand-based soils. In Fig. 8, actual field measurements of V_s and N for sandy soils are contrasted with the equations advised by six other researchers, namely Hanumantharao and Ramana [26], Maheshwari et al. [17], Imai [11], Okamoto et al. [19], Pitilakis et al. [9], and Raptakis et al. [22]. The hypothesized link between V_s (m/s) and N levels for sandy soils is shown in Fig. 9 along with the correlation between V_s and N. R² = 0.9672 is the correlation coefficient for this relationship.

${V_s}=140.85{N^{0.5872\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)$

In Fig. 8, the suggested connection for sandy soils (Eq. 3) and actual correlations are contrasted.

Clayey Soils

60 data pairs (V_s and N) were used in the regression analysis for clayey soils. In Fig. 10, the field data are compared to the equations put out by five other researchers, namely Imai [11], Lee [13], Pitilakis et al. [9], Raptakis et al. [22], and Uma Maheswari et al. [25]. Figure 11 illustrates the link between V_s and N, and the following equation, with correlation coefficient R² = 0.9954, proposes a relationship between V_s (m/s) and N levels for clayey soils.

$${V_s}=143.2{N^{0.5815\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(4)$$

Table 5

An overview of the suggested connections
S. no.	Type of soil	Correlation	R²
1	All Soils	${V_s}=141.84{N^{0.5853}}$	$0.9931$
2	Sandy Soils	${V_s}=140.85{N^{0.5872}}$	$0.9672$
3	Clayey Soils	${V_s}=143.2{N^{0.5815}}$	$0.9954$

It is noted that the number of blows (N) used in Table 4 are uncorrected SPT blows. It can be seen that for the present data pairs, the correlation coefficient (R²) of all soils and clayey soils are very close because most of the data pairs in all soils are that of clayey soils, but the correlation for sandy soils is slightly different than the other two.

In this study, a novel connection between V_s and N for the Isfahan Metro Line 2 has been attempted. This has been done independently for the three scenarios of (a) all soils, (b) sandy soils, and (c) clayey soils. 22 boring logs in the area were subjected to field testing, including SPT and MASW, for this purpose. The findings gathered are reported in this study.

The correlations put out in this research are crucial because they might be applied to the region's seismic microzonation. Such connections have not before been mentioned for this area. Since N values are frequently easy to obtain, these equations can be utilized to determine shear wave velocity (V_s). In ground response analysis, the (V_s) is a crucial metric that aids in identifying amplification at a location. This is therefore helpful for assessing earthquake damage and determining how much ground repair should be done.

Conflict of Interests

No government or corporate entity has provided funding to the writers of this article. The writers of this work have no competing interests.

Acknowledgements

Acknowledgments for this research, first authors; Second and third contributed to writing this article. We appreciate the critical reading by arbitration committee and we will be acknowledging our gratitude for enlightening suggestion and insightful comments.

Ansari A, Zahoor F, Rao KS, Jain AK (2022) Seismic hazard assessment studies based on deterministic and probabilistic approaches for the Jammu region, NW Himalayas. Arab J Geosci 15(11):1081
Akbarimehr D, Fakharian K (2021) Dynamic shear modulus and damping ratio of clay mixed with waste rubber using cyclic triaxial apparatus. Soil Dyn Earthq Eng 140:106435
Athanasopoulos GA (1995) Empirical correlations Vso-NSPT for soils of Greece: a comparative study of reliability. Proceedings of the 7th International Conference on Soil Dynamics and Earthquake Engineering Computation Mechanics Publications. Southampton, Boston, pp 19–25
Alhuay-León CG, Trejo-Noreña PC (2021) The empirical correlation between shear wave velocity and penetration resistance for the eolian sand deposits in the city of Olmos-Peru. Dyna 88(217):247–255
Bashir K, Debnath R, Saha R (2022) Estimation of local site effects and seismic vulnerability using geotechnical dataset at flyover site Agartala India. Acta Geophys 70(3):1003–1036
Forte G, Chioccarelli E, De Falco M, Cito P, Santo A, Iervolino I (2019) Seismic soil classification of Italy based on surface geology and shear-wave velocity measurements. Soil Dyn Earthq Eng 122:79–93
Huynh QT, Lai VQ, Boonyatee T, Keawsawasvong S (2022) Verification of soil parameters of hardening soil model with small-strain stiffness for deep excavations in medium dense sand in Ho Chi Minh City, Vietnam. Innovative Infrastructure Solutions 7(1):15
Hunter JA, Benjumea B, Harris JB, Miller RD, Pullan SE, Burns RA, Good RL (2002) Surface and downhole shear wave seismic methods for thick soil site investigations. Soil Dyn Earthq Eng 22(9–12):931–941
Hussien MN, Karray M (2015) Shear wave velocity as a geotechnical parameter: an overview. Can Geotech J 53(2):252–272
Hasancebi N, Ulusay R (2007) Empirical correlations between shear wave velocity and penetration resistance for ground shaking assessments. Bull Eng Geol Environ 66:203–213
Imai T, Tonoughi K (2021) February). Correlation of N value with S-wave velocity and shear modulus. Penetration Testing. Routledge, pp 67–72
IS : 2720-Part 4. (1985). Methods of test for soils: grain size analysis
Jallow A, Ou CY, Lim A (2019) Three-dimensional numerical study of long-term settlement induced in shield tunneling. Tunn Undergr Space Technol 88:221–236
Kushwaha SS, Kishan D, Dindorkar N (2018) Stabilization of expansive soil using eko soil enzyme for highway embankment. Materials today: proceedings, 5(9), 19667–19679
Kumar A, Satyannarayana R, Rajesh BG (2022) Correlation between SPT-N and shear wave velocity (VS) and seismic site classification for Amaravati city, India. J Appl Geophys 205:104757
Lancelle CE, Baldwin JA, Lord N, Fratta D, Chalari A, Wang HF (2021) Using distributed acoustic sensing (DAS) for multichannel analysis of surface waves (MASW). Distributed Acoustic Sensing in Geophysics: Methods and Applications, 213–228
Maheshwari BK, Mahajan AK, Sharma ML, Paul DK, Kaynia AM, Lindholm C (2013) Relationship between shear velocity and SPT resistance for sandy soils in the Ganga basin. Int J Geotech Eng 7(1):63–70
Muley P, Maheshwari BK, Kirar B (2022) Liquefaction potential of sites in Roorkee Region using SPT-Based methods. Int J Geosynthetics Ground Eng 8(2):26
Okamoto T, Kokusho T, Yoshida Y, Kusuonoki K (1989), October Comparison of surface versus subsurface wave source for P–S logging in sand layer. In Proc. 44th Ann. Conf. JSCE (Vol. 3, pp. 996-7)
Panjamani AP, Ingale SG (2021) Status quo of standard penetration test in India: a review of field practices and suggestions to incorporate in Is 2131. Indian Geotech J 51:421–434
Rahimi S, Wood CM, Wotherspoon LM (2020) Influence of soil aging on SPT-Vs correlation and seismic site classification. Eng Geol 272:105653
Romero-Ruiz A, Linde N, Keller T, Or D (2018) A review of geophysical methods for soil structure characterization. Rev Geophys 56(4):672–697
Raptakis DG, Anastasiadis SAJ, Pitilakis KD, Lontzetidis KS (1995), August Shear wave velocities and damping of Greek natural soils. In Proc. 10th European Conf. Earthquake Engg., Vienna (Vol. 477482)
Sykora DW (1983) Correlations of in situ measurements in sands of shear wave velocity, soil characteristics, and site conditions (Doctoral dissertation, University of Texas at Austin)
Tuttle MP, Hartleb R, Wolf L, Mayne PW (2019) Paleoliquefaction studies and the evaluation of seismic hazard. Geosciences 9(7):311
Uma Maheswari R, Boominathan A, Dodagoudar GR (2010) Use of surface waves in statistical correlations of shear wave velocity and penetration resistance of Chennai soils. Geotech Geol Eng 28:119–137
Xiao S, Zhang J, Ye J, Zheng J (2021) Establishing region-specific N–Vs relationships through hierarchical Bayesian modeling. Eng Geol 287:106105

Shear Wave Velocity (Vs) and SPT Resistance (N) Correlation for the Isfahan Metro, Iran

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Geotechnical Investigation