Effects of Cyclic Freezing and Thawing on the Shear Behaviors of an Expansive Soil under a Wide Range of Stress Levels

doi:10.21203/rs.3.rs-507911/v1

Download PDF

Research Article

Effects of Cyclic Freezing and Thawing on the Shear Behaviors of an Expansive Soil under a Wide Range of Stress Levels

https://doi.org/10.21203/rs.3.rs-507911/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 24 Jan, 2022

Read the published version in Environmental Earth Sciences →

You are reading this latest preprint version

The focus of this paper is directed towards investigating the influence of multiple freeze-thaw (FT) cycles on the stress-strain relationships during undrained shearing for an expansive soil under a wide range of confining stresses (σ_c) from 0 to 300 kPa. Different numbers of FT cycles were applied to compacted specimens. The influence of FT cycles on the soil’s structure was investigated using mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) tests. FT impacted specimens were subjected to consolidated undrained (CU) shear tests with pore pressure measurement (σ_c = 10 to 300 kPa) and unconfined compression (UC) tests (σ_c = 0 kPa) to derive the shearing stress-strain relationships and the associated mechanical properties including (i) failure strength (q_u), elastic modulus (E_u), effective and apparent cohesion (c’ and c), and effective and apparent friction angle (ϕ’ and ϕ) obtained from CU tests and (ii) q_u and reloading modulus (E_1%) and stress (S_u1%) at 1% strain obtained from UC tests. Testing results show that FT cycles mainly influence the soil’s macropores with diameters between 5 and 250 microns. Cracks develop during FT cycles and result in slight swelling which contributes to an increase in the global volume of the soil specimens. There is a significant reduction in the investigated mechanical properties after FT cycles. They typically achieve equilibrium after about 6 cycles. The shearing stress-strain curves transits from strain-softening to strain-hardening as the confining stress increases. An empirical model is developed to describe the strain-softening behavior of the specimens under low confining stresses. The model is simple to use and well describes all stress-strain curves obtained in this study that show strain-softening characteristics.

Environmental Engineering

Environmental Policy

Expansive soil

Freeze-thaw

Microstructure

Volumetric change

Shear behavior

Table 1 Basic index properties of the tested expansive soil
Properties	Values	Testing standards
Specific gravity, G_s	2.68	ASTM D854 (2014)
Liquid limit, w_L(%)	42.84	ASTM D4318 (2018)
Plastic limit, w_P (%)	22.40
Plasticity index, I_P	20.44
Sand (%)	18	ASTM D6913 (2017) ASTM D7928 (2017)
Silt (%)	70
Clay (%)	12
Free swelling ratio (%)	67	ASTM D4546 (2018)
pH value	8.2	ASTM D4972 (2019)
USCS	CL	ASTM D2487 (2011)

Table 2 Evolution of the e_MIPduring FT cycles
No. of cycles	FT cycles
No. of cycles	Δe_MIP,A	Δe_MIP,B	Δe_MIP,C	e_MIP,0.01
10	0.059	0.272	0.177	0.508
6	0.059	0.286	0.180	0.525
4	0.056	0.293	0.183	0.532
1	0.059	0.336	0.123	0.518
0	0.062	0.345	0.146	0.553

Table 3 Values of parameters in Eq. (1) for unconfined compression tests
Parameter types	As-compacted specimens		Saturated specimens
Parameter types	α	β	α	β
q_u	0.815	0.482	0.893	0.721
E_1%	1.185	0.178	1.400	0.450
S_u1%	1.551	0.642	2.456	0.660

Table 4 Values of parameters in Eq. (1) for consolidated undrained tests
Parameter types	σ_c (kPa)	α	β	R²	Parameter types	σ_c (kPa)	α	β	R²	Parameter types	σ_c (kPa)	α	β	R²
q_u	10	0.282	0.150	0.968	c’	10	0.083	1.575	0.712	c	10	0.161	0.082	0.961
	20	0.278	0.260	0.968		20	0.079	1.338	0.858		20	0.080	0.186	0.975
	30	0.435	0.187	0.915		30	0.309	0.200	0.964		30	0.204	0.147	0.938
	50	0.391	0.466	0.983		50	0.457	0.225	0.982		50	0.269	0.176	0.987
	100	0.418	0.429	0.995		100	0.562	0.221	0.970		100	0.416	0.182	0.957
	200	0.329	0.574	0.967		200	0.798	0.205	0.999		200	0.536	0.319	0.998
	300	0.248	0.465	0.924		300	0.699	0.274	0.962		300	0.620	0.303	0.994
E_u	10	0.301	0.327	0.980	ϕ’	10	0.421	0.110	0.979	ϕ	10	0.329	0.332	0.988
	20	0.408	0.269	0.985		20	0.425	0.116	0.967		20	0.318	0.313	0.993
	30	0.565	0.304	0.998		30	0.333	0.131	0.828		30	0.283	0.323	0.978
	50	1.152	0.377	0.998		50	0.436	0.072	0.984		50	0.254	0.310	0.987
	100	0.776	0.399	0.999		100	0.173	0.200	0.975		100	0.184	0.232	0.957
	200	0.672	0.237	0.997		200	0.134	0.158	0.973		200	0.130	0.163	0.948
	300	0.655	0.348	0.957		300	0.174	0.079	0.933		300	0.067	0.290	0.989

Table 5 Values of parameters in Eq. (4) for describing the strain- stabilization and hardening behavior of specimens in CU tests
Number of cycles	Confining pressures (kPa)	a (×10^-5)	b	R²
N_FT=0	50	4.301	0.007	0.997
	100	2.299	0.005	0.999
	200	2.687	0.003	0.999
	300	1.634	0.002	0.999
N_FT=1	50	5.555	0.008	0.998
	100	3.740	0.005	0.999
	200	2.759	0.004	0.999
	300	2.118	0.003	0.999
N_FT=4	50	10.068	0.009	0.998
	100	4.713	0.006	0.999
	200	3.521	0.004	0.999
	300	2.723	0.003	0.999
N_FT=6	50	12.112	0.009	0.997
	100	5.045	0.006	0.999
	200	4.356	0.004	0.999
	300	3.142	0.003	0.999
N_FT=10	50	13.973	0.009	0.997
	100	5.722	0.007	0.997
	200	4.896	0.004	0.999
	300	3.556	0.003	0.998

Table 6 Values of parameters in Eq. (5) for describing the strain-softening behavior of specimens in CU tests
Number of cycles	Confining pressures (kPa)	a (×10^-4)	b	λ	κ	n	m	R²
N_FT=0	10	2.292	0.013	0.848	14.329	-0.2.680	-0.243	0.998
	20	-4.428	-0.039	-3.402	20.940	-2.475	-0.120	0.999
	30	-65.481	-0.008	-0.897	27.968	-2.343	-0.084	0.999
N_FT=1	10	-15.600	-0.106	-6.462	16.804	-5.135	-0.155	0.997
	20	-7.052	-0.053	-4.221	26.131	-2.511	-0.159	0.999
	30	-1.991	-0.024	-2.282	25.552	-4.147	-0.086	0.999
N_FT=4	10	-2.535	-0.016	-0.909	21.310	-5.456	-0.168	0.999
	20	-3.525	-0.064	-2.189	26.189	-3.321	-0.202	0.998
	30	-7.779	-0.048	-4.378	67.053	-2.880	-0.102	0.999
N_FT=6	10	-12.2	-0.069	-3.668	25.852	-5.760	-0.170	0.998
	20	-4.485	-0.052	-4.406	28.075	-3.072	-0.216	0.998
	30	7.669	0.041	3.425	33.599	-2.016	-0.170	0.999
N_FT=10	10	-9.439	-0.045	-2.468	16.164	-4.247	-0.218	0.997
	20	-6.987	-0.043	-2.953	26.852	-3.641	-0.155	0.999
	30	1.746	0.011	0.898	26.508	-5.847	-0.080	0.999

Download PDF

Journal Publication

published 24 Jan, 2022

Read the published version in Environmental Earth Sciences →

Editorial decision: Reject & Resubmit
31 Jul, 2021
Reviews received at journal
31 May, 2021
Reviewers invited by journal
31 May, 2021
Editor assigned by journal
08 May, 2021
First submitted to journal
07 May, 2021

You are reading this latest preprint version

Effects of Cyclic Freezing and Thawing on the Shear Behaviors of an Expansive Soil under a Wide Range of Stress Levels

Status:

Journal Publication

Version 1

Abstract

Figures

Full Text

Tables

Status:

Journal Publication

Version 1