Constrained Modulus Research Articles

Determination of Constrained Modulus of Granular Soil from In Situ Tests—Part 2 Application

The paper demonstrates how the concepts presented in the companion paper: “Determination of Constrained Modulus of Granular Soil from In Situ Tests—Part 1 Analyses” can be applied in practice. A settlement design based on the tangent modulus method is described. Extensive in situ tests were performed on a well-documented test site consisting of sand with silt and clay layers. The field tests comprised different types of penetration tests, such as the cone penetration test, the flat dilatometer, and the seismic down-hole test. The modulus number and the constrained tangent modulus were derived from the cone penetration test with pore water pressure measurement and the flat dilatometer test. In addition, the shear wave speed was determined from two seismic down-hole tests, from which the small-strain shear modulus could be evaluated. The constrained modulus obtained from the cone penetration test with pore water pressure measurement (CPTU) and the flat dilatometer (DMT) was compared with that from the seismic down-hole tests. The importance of the stress history on the constrained modulus was demonstrated. The range of modulus numbers, derived from different in situ tests, compares favorably with empirical values reported in the literature.

Prediction of constrained modulus for granular soil using 3D discrete element method and convolutional neural networks

To efficiently predict the mechanical parameters of granular soil based on its random micro-structure, this study proposed a novel approach combining numerical simulation and machine learning algorithms. Initially, 3500 simulations of one-dimensional compression tests on coarse-grained sand using the three-dimensional (3D) discrete element method (DEM) were conducted to construct a database. In this process, the positions of the particles were randomly altered, and the particle assemblages changed. Interestingly, besides confirming the influence of particle size distribution parameters, the stress-strain curves differed despite an identical gradation size statistic when the particle position varied. Subsequently, the obtained data were partitioned into training, validation, and testing datasets at a 7:2:1 ratio. To convert the DEM model into a multi-dimensional matrix that computers can recognize, the 3D DEM models were first sliced to extract multi-layer two-dimensional (2D) cross-sectional data. Redundant information was then eliminated via gray processing, and the data were stacked to form a new 3D matrix representing the granular soil's fabric. Subsequently, utilizing the Python language and Pytorch framework, a 3D convolutional neural networks (CNNs) model was developed to establish the relationship between the constrained modulus obtained from DEM simulations and the soil's fabric. The mean squared error (MSE) function was utilized to assess the loss value during the training process. When the learning rate (LR) fell within the range of 10-5–10-1, and the batch sizes (BSs) were 4, 8, 16, 32, and 64, the loss value stabilized after 100 training epochs in the training and validation dataset. For BS = 32 and LR = 10-3, the loss reached a minimum. In the testing set, a comparative evaluation of the predicted constrained modulus from the 3D CNNs versus the simulated modulus obtained via DEM reveals a minimum mean absolute percentage error (MAPE) of 4.43% under the optimized condition, demonstrating the accuracy of this approach. Thus, by combining DEM and CNNs, the variation of soil's mechanical characteristics related to its random fabric would be efficiently evaluated by directly tracking the particle assemblages.

Determination of engineering properties of cementitiously stabilised aggregates using ultrasonic pulse velocity

Non-destructive testing methods, such as Ultrasonic Pulse Velocity (UPV), have been widely used to assess the quality and performance of cementitious stabilised aggregates. The present study reveals the robust relationship of UPV and constrained modulus (CM) with unconfined compressive strength (UCS), modulus of rupture/flexural strength (MoR), and flexural modulus (FM) in aggregates stabilised with five different stabiliser combinations, including cement, cement-ground granulated blast furnace steel slag (GGBS), cement-fly ash and cement with two commercial chemical admixtures. The high accuracy of UPV and CM in estimating destructive test parameters and approximating challenging tests like FM is convincingly demonstrated with strong correlations (R² > 0.80) and standard error ratios (Se /Sy < 0.35). Power law and logarithmic curves prove suitable for modelling the relationships between strength and stiffness with UPV and CM, respectively. Notably, however, the study reveals significant variations in correlating parameters across different cementitious stabilisers within the same mix design, emphasising the strong dependence on the specific cementitious material type. Overall, this work offers valuable insights into the use of non-destructive parameters, UPV and CM, for the characterisation of stabilised aggregates based on cementitious material type and different curing conditions.

Constrained modulus of fine-grained soils from in situ-based correlations and comparison with laboratory tests

The Constrained Modulus of soil is an important parameter to quantify compressibility of soils and calculate consolidation settlements, especially for clays. It is often expressed in terms of 1D constrained modulus, M or its inverse coefficient of volume change, mv. One method that has been suggested to assess M is from Cone Penetration Testing (CPTU) measurements through various correlations. Although, this is sometimes difficult, because of uncertainties regarding the appropriate stress, σ’v0, which are highly affected by the groundwater and bulk density γ, of soils. The usual method to measure M (or mv) is from oedometer tests in laboratory. Correlating in situ tests with laboratory tests results is crucial to increase the quality of soils strengths and stiffness information for design. However, most of the times it is a challenging process, which involves many uncertainties from different soils’ tests. This paper will look at comparison of CPTU derived M to oedometer tests taking into consideration various types of soils mostly from well-documented testbed sites where high quality in situ (CPTU for all sites and SDMT where available) and oedometer tests are carried out. The importance of CPTU measurements and site-specific correlations with laboratory tests to establish unique soil type coefficients for use in equations to derive CPTU-based M will be highlighted.

Specific Storage or Elastic Modulus of Solid Matrix in Aquifers and Aquitards—Results from Slug Tests: A Review and a Clarification

Abstract Hydrogeology defines specific storage, Ss, to quantify the ability of a saturated layer to release or take water when the hydraulic head is changed, resulting in a change in the solid matrix volume. ASTM D4104/D4104M-20, Standard Practice for (Analytical Procedures) Determining Transmissivity of Nonleaky Confined Aquifers by Overdamped Well Response to Instantaneous Change in Head (Slug Tests), has a method to assess the Ss value. The article explains how continuum mechanics relate Ss to the constrained (one-dimensional vertical) elastic modulus, E′, of the solid matrix. As a result, Ss has a limited range of values for soil and rock, but this limitation has not received enough attention. Continuum mechanics have already proven that slug tests cannot give Ss, contrary to the opinion of a few slug test users. Short tables clarify and summarize the strangeness of the slug test theory with Ss. The Ss values are in the 10−4–10−7 m−1 range according to continuum mechanics, but the slug test theory yields a 100–10−20 range. The comparison shows that the slug test theory with Ss gives only 5 % of realistic Ss values. The tests in soil and rock often yield Ss values that are those of materials either stiffer that steel or softer than peat. An example clarifies this finding. A monitoring well (MW) was tested with three sets of sensors having different calibration errors: the three test datasets yielded a wide Ss range for the sand tested by the MW. Recommendations are made to avoid misinterpreting test data and improve current standards. The slug test theory with Ss is based on errors in math and physics, and its supporters have so far delayed the use of physically correct methods in ASTM standards. The article does not question the ability of pumping tests and geophysical methods to extract the value of Ss or E′.

The Use of CPTU and DMT Methods to Determine Soil Deformation Moduli—Perspectives and Limitations

Abstract The article presents the concept of determining constrained modulus—M0 , initial shear modulus—G0 , Young modulus—E, and rigidity index—IR on the basis of parameters from static penetration tests CPTU (Piezocone Penetration Testing), SCPTU (Seismic Piezocone Penetration Testing) and dilatometer tests DMT (Flat Dilatometer Test), SDMT (Seismic Flat Dilatometer Test). The basis for constructing the empirical relationships between the mentioned modules and parameters from the CPTU and DMT studies was to determine the factors that affect these relationships. The article discusses the impact of the following factors; geological and geotechnical conditions, conditions of recording measurements in CPTU and DMT tests, factors relating to the CPTU and DMT testing methods, factors affecting reference parameters from laboratory tests, factors related to subsoil properties. The basis for obtaining the empirical relationships for determining the analyzed modules and rigidity index were extensive research of the soils of various origins, in Poland. Measurement uncertainties and factors influencing the recorded parameters in the CPTU study were documented by the studies of the Norwegian Geotechnical Institute and the former Department of Geotechnics of the Agricultural University in Poznań. In these studies, penetrometers from several reputable manufacturers were used. The article summarizes the established empirical relationships for individual modules, taking into account the effect of overconsolidation. It also comments on the interrelationship between constrained modulus M0 from CPTU and DMT test for soils in Poland.

Laboratory Small-Strain Stiffness Measurement Using Distributed Acoustic Sensing

Abstract This article introduces a novel method for measuring the small-strain stiffness of materials at the laboratory scale using the emerging technology of distributed acoustic sensing (DAS). This setup involves modifying the traditional free-free resonant column test by wrapping the DAS fiber optic cable around the sample. Tests are conducted using both active and passive sources. Sample resonances measured by DAS demonstrate a high degree of consistency with conventional accelerometer, indicating that DAS is accurate and reliable at the kilohertz scale. To extract the sample resonant frequency from passive sources in laboratory environments (such as cooling fan noise, mixer vibrations, and manual tamping procedure), the auto-correlation method is employed to enhance the amplitude spectrum’s signal-to-noise ratio. The measured transverse resonance excited by passive sources aligns well with that measured under active sources, suggesting the potential for using nonstationary ambient vibrations for long-term monitoring. The study also reveals that impulse-like forces are more suitable for exciting distinguishable resonant frequency compared to continuous but weak ambient vibrations. In a benchmark study, the repeatability of DAS measurements is verified using fabricated samples with known and stable stiffness. The measured constrained and shear moduli are found to be consistent among DAS, accelerometer, and ground-truth values, confirming the robustness and accuracy of the DAS-based free-free resonance column test. To further demonstrate the practical application of the proposed DAS-based system, a 28-day monitoring of cement-stabilized soil is conducted. The small-strain stiffness evolution is successfully captured by DAS, with marginal differences between measurements under active and passive sources. This outcome highlights the potential quality assurance scenarios for DAS because of its distributed properties and rapid data acquisition capabilities.

Analysis of Using the Empirical Model of Organic Soil Consolidation to Predict Settlement

Abstract The paper describes two models for determining the constrained elasticity modulus of organic soils based on the settlement of an overloading embankment. In these methods, based on the settlement of the embankment of the load exerted on the subsoil, using the inverse problem, it is possible to determine the constrained modulus. A parameter determined in this way can also be determined during consolidation. Changes in the settlement at successive stages of consolidation can be used to determine the constrained modulus of the organic soil at a given point in time. Assuming a “temporarily stable” (quasi-stationary) state at each analysed stage of consolidation. The constrained elasticity modulus was determined for the settling at a given moment. constrained modulus tests of organic soils were carried out for two embankments previously described in the literature. In this case, the modulus was also analysed during consolidation. These embankments are founded on peat and peat-gyttja substrates. In both cases, the layer of organic soil was 4 m. The presented methods with the assumption of a one-dimensional state of deformation, despite the state of spatial stress, can be used during construction using the “design and build” technology. The constrained modulus determined from the embankment overload will represent the actual deformations – volumetric deformations (including other deformations that actually occurred) during the consolidation period. The paper was concluded with several conclusions.

Comparison of the Number of Compactor Passes and the Constrained Modulus of a Compacted Volcanic Soil

Volcanic soil is often used as fill material in road embankment construction in Java island-Indonesia. An understanding of the engineering properties of compacted volcanic soils is needed, especially during the preliminary design phase and during the detailed design phase of the road embankment. Carrying out a field compaction trial test will significantly assist in the design of the compaction process of the road embankment construction. Selecting the correct number of passes from the compactor and the engineering properties of compacted volcanic soils can be obtained from field compaction trial tests. Constrained modulus is one of the engineering properties that can indicate the stiffness of the fill material used in a road embankment. This study aims to determine the constrained modulus of compacted volcanic soil and compare it to the number of passes of a compactor from the field compaction trial test. The volcanic soil used in this study is classified as pumiceous tuff, which is derived from older volcanic rocks. The highest value of the oedometer modulus of compacted volcanic soils is 10.38 MPa which comes from eight (8) times passes of smooth drum roller conducted on field compaction trial test.

The Influence of Mortar's Poisson Ratio and Viscous Properties on Effective Stiffness and Anisotropy of Asphalt Mixture.

This paper presents the results of a research study and analysis conducted to determine the degree of anisotropy of asphalt concrete in terms of its initial elastic properties. The analysis of asphalt concrete was focused on determining the effective constrained stiffness modulus in three mutually perpendicular directions based on the finite element method. The internal structure of the asphalt concrete was divided into the mortar phase and the mineral aggregate phase. Static creep tests using the Bending Beam Rheometer were conducted for the mortar phase to fit the rheological model. The aggregate arrangement and orientation were analysed using an image analytical technique for the mineral phase. The Finite Element Method (FEM) meshes were prepared based on grey images with an assumption of plane strain in 2D formulation. Using the FEM model, the tension/compression tests using selected characteristic directions were conducted, and the effective constrained stiffness moduli were estimated. This study showed a dominant horizontal direction for all coarse aggregates resulting from the normal force of the road roller and paving machines during laying and compaction on a road site. Depending on the values of the mortar's mechanical parameters and the load direction, the effective stiffness modulus might differ by ±20%. Based on the FEM analysis, this result was proven and commented on through an effective directional modulus evaluation and a presentation of internal stress distribution. Depending on the shape and orientation of the aggregates, it was possible to observe local "stress bridging" (transferring stresses from aggregate to aggregate when contacting). Moreover, the rheological properties of the mortar were considered by assuming two limiting situations (instantaneous and relaxed moduli), determining the bands of all possible solutions. In the performed FEM analysis, the influence of the Poisson ratio was also considered. The analysed asphalt concrete tends to be isotropic when the Poisson's mortar ratio is close to the value of 0.5, which agrees with the physical expectations. The obtained results are limited to particular asphalt concrete and should not be extrapolated to other asphalt mixture types without prior analysis.

Effect of clay mineral content on soil strength parameters

The impact of clay mineralogy on engineering properties relevant to road design, such as the strength and stiffness of road materials, has recently been the subject of intensive investigations, aiming at providing indirect measures of soil performance out of mineralogical data. This study deals with the effects of clay minerals on soil strength, expressed in terms of California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS), and stiffness, represented by the constrained modulus, which are commonly used as engineering properties for pavement materials. The study is performed on six clayey soils (S1-S6) of different geographic origins. Five of the six soils are highly plastic, potentially swelling, and one is kaolinitic soil. The mineralogical characteristics of the samples were analyzed through X-ray diffraction (XRD). The testing program included Atterberg limits, sieve analysis, CBR, UCS, and consolidation tests. The measured properties of the samples were compared in light of the mineralogical composition of the soils. The investigation showed that the kaolinite mineral is significantly more effective than the montmorillonite in reducing the plasticity of the clays. Higher strength indicators (CBR and UCS) were observed for samples with high kaolinite content (S4, S5, and S6). Moreover, the kaolinitic soil samples are characterized by a larger constrained modulus (Ec) than the other samples.

Methods Development for the Constrained Elastic Modulus Investigation of Organic Material in Natural Soil Conditions.

Compressibility is one of the most important mechanical properties of soil. The parameter that characterizes compressibility is the constrained modulus of elasticity. Knowledge of this is important to calculate the settlement of a structure foundation on peat material. According to soil classification by EN ISO 14688-2, peat is an organic soil that contains min. 20% organic matter. It is a highly organic type of soil. Peat material has large compressibility. The value of the constrained elasticity modulus for peat is ca. 400 kPa, while it may be ca 1.0–1.6 MPa for consolidated peat. Due to the extensive range of the modulus, experimental research in this field is proposed. It is suggested to load the peat material layer with an embankment and to determine its total settlement. Based on this, a program was developed to determine the settlement–strain relationship. The authors propose an approach according to two models: the first is based on constant stress distribution in the soil with an oedometer test. The second considers the variability of stresses in the soil and the influence of the loaded area. Both methods were tested based on numerical simulations, and then an experimental field in Szczecin was used. The formulae for the constrained modulus of elasticity measurement were derived; in practical conditions, a uniaxial deformation state can be used with the combination of the total settlement.

In situ characterization of nonlinear soil behavior of vertical ground motion using KiK-net data

Strong vertical ground motion has significant influences on the seismic response of engineered structures. However, the soil nonlinearity of vertical ground motion has received less attention compared with that of horizontal ground motion. In this study, seismic observations from KiK-net were used to investigate the soil nonlinearity of vertical ground motion. A new fitting formula was proposed to estimate the global constrained modulus degradation curve considering the influence of groundwater. The proposed formula was verified by the higher goodness of fit compared with a widely used fitting formula and the consistency with the theoretical solution from a former study. The order of the magnitude of the normal strain linear threshold was approximately 10−6 which is the same as that of the shear strain. Furthermore, different from the shear modulus, the constrained modulus of the selected stations decreased quickly when normal strain was between 10−5 and 10−4, and the reduction speed slowed down when it was above 10−4. This result was consistent with the theoretical result based on the laboratory test data from a previous study. Using the fitted relationships between the soil strain and peak ground acceleration (PGA), we found the PGA threshold for vertical nonlinearity could be as low as 30 cm/s2 and was generally higher than that for horizontal nonlinearity. Moreover, the difference in reduction between the shear modulus and constrained modulus after a strong earthquake was investigated which could be related to the change in Poisson’s ratio.

Vertical compression of soft clay within PVD-improved zone under vacuum loading: Theoretical and practical study

Reliably estimating soil vertical compression under vacuum loading is still challenging for geotechnical engineers. In this paper, the soil vertical compression within the prefabricated vertical drain (PVD)-improved zone under vacuum pressure was investigated based on the theoretical analysis, reported laboratory tests and the case histories. A theoretical equation was developed to evaluate the effect of lateral displacement on the soil vertical compression. The observed small overall lateral-to-vertical strain ratio at the perimeter of the PVD-improved zone soil showed that the vertical compression of PVD-improved zone was close to one-dimensional (1-D) state, but 1-D compression method yielded smaller predictions than the measurements from the case histories. The back-analyzed soil modulus of the natural soft clay in Shanghai Disneyland Resort project showed considerable degradation as compared to the corresponding constrained modulus from the laboratory test. Such degradation could be due to the soil disturbance caused by PVD installation. The 1-D compression method was modified by introducing two factors to consider the effect of soil lateral displacement and to correct the constrained modulus due to the soil disturbance caused by PVD installation, respectively. The recommendations were provided after applying the proposed method to a case history.

Estimation of stress state-dependent elastic modulus of pavement structure materials using one-dimensional loading test

An important key parameter used in mechanistic pavement engineering design is the resilient modulus (Mr ) or elastic modulus (E) of pavement structure materials. Although the Mr value can be estimated from the California Bearing Ratio (CBR) value by various empirical equations, it is rather inaccurate, and importantly, its dependency on the bulk stress (θ) cannot be taken into account. This paper presents an alternative method for evaluating the E value by a one-dimensional (1D) compression test performed on the sample prepared as usual in the CBR mould. The materials studied consist of sand, lateritic soil, and crushed rock. The CBR mould was modified such that the mobilized θ value can be measured. The nominal constrained modulus (M o) was determined with a 1D compression test using this mould. Another series of triaxial compression (TC) tests was performed to determine the quasi-elastic Young’s modulus (E eq). Then, the E eq value was converted to the corresponding constrained modulus (M TC). It was found that bedding errors are responsible for the constrained modulus difference (ΔM = M TC − M o), which consists of (i) the independent part of θ (ΔM 1) and (ii) the dependent part of θ (ΔM 2). By performing a 1D compression test as described above, both the M o and θ values can be determined, and the ΔM value can be obtained from the ΔM − θ relationship. Then, the true constrained modulus (M 1D) can be determined. This M 1D can then be converted to the E value for use in a pavement engineering design.

Small-Strain and Large-Strain Modulus Measurements with a Consolidation Device

Abstract By using a back-pressure saturated, constant rate-of-strain consolidation device with bender elements (BP-CRS-BE), values of large-strain constrained modulus (M) and small-strain shear modulus (Gmax) were obtained from tests performed on kaolinite soil specimens. The methodology and procedures that were utilized to obtain values of M, Gmax, large-strain shear modulus (G), drained Poisson’s ratio (ν), horizontal effective stress (σh′), vertical effective stress (σv′), specific volume (v), coefficient of lateral earth pressure during unloading (K0,UL), and drained friction angle (ϕ′) are discussed herein. The following five observations were made. (1) The Gmax values increased with increasing values of σv′ and decreased with increasing values of the overconsolidation ratio (OCR). (2) The Gmax values that were obtained by utilizing correlations and the large-strain BP-CRS-BE testing data (identified as GmaxCRS,p′), which were back-calculated by considering the modulus reduction, matched the Gmax values that were obtained from the bender element measurements within the BP-CRS-BE device (Gmax,BE). (3) The ν values increased with increasing σv′ values but decreased with the increasing void ratio (e) values. (4) The K0,UL values increased with increasing OCR values. (5) The ϕ values that were calculated for the soil that was tested within the BP-CRS-BE device by using the K0,UL-OCR data that were obtained from the BP-CRS-BE device (21.2°, 16.0°, and 24.7°) were similar to the ϕ′ values that were obtained from modified Mohr-Coulomb diagram from triaxial tests on the same soil (20.7°).

Constrained Compression Models for Tire-Derived Aggregate-Sand Mixtures Using Enhanced Large Scale Oedometer Testing Apparatus

Tire derived aggregates have recently been in wide use both in industry and engineering applications depending on the size and the application sought. Five different contents of tire derived aggregates (TDA) were mixed with sand thoroughly to ensure homogeneity. A series of large scale oedometer experiments were conducted to investigate the compressibility properties of the mixtures. Tire shreds content, TDA aspect ratio, skeletal relative density and overburden pressure are studied parameters. Constrained deformation modulus and coefficient of earth pressure at rest are measured parameters. All tests were conducted at seven overburden pressure levels. It was concluded that deformability of TDA-sand mixture increases with soft inclusion. Overburden pressure and skeletal relative density are also important parameters which render more rigidity and less lateral earth pressure coefficient accordingly. TDA size or aspect ratio was shown to have minor effect at least for the constrained strain conditions encountered in current study. An EPR-based parametric study and also sensitivity analyses based on cosine amplitude method revealed quantitative evaluation of the relative importance of each input parameter in varying deformation and lateral earth pressure coefficient as the outputs.

Evaluation of dynamic properties of calcareous sands in Egypt at small and medium shear strain ranges

Calcareous sand deposits are widely distributed along the shoreline of Mediterranean Sea in Egypt; known as the North Coast area, which covers promising areas for industrial and touristic activities. An experimental study was conducted to evaluate the shear modulus and damping ratio at small and medium shear strain ranges of sands procured from two districts along the North Coast using fixed-free resonant column apparatus. In addition, flexural and constrained moduli, flexural damping ratio, and Poisson's ratio were estimated. Effects of effective confining stress, void ratio, and saturation condition (saturated versus dry) on evaluated dynamic properties were investigated. The maximum shear modulus increased with increasing the effective confining stress exponentially with relatively high exponent values compared to those reported for siliceous sands. The effect of void ratio on shear modulus was more pronounced at low void ratios and maximum shear modulus increased as the void ratio decreased. Dry cemented sands characterized with their irregular and rough particles showed lower maximum shear moduli and higher stress exponents compared to saturated sands. Natural cementation was found to indirectly influence the dynamic properties of sands as it alters the inter-particle properties.

Stiffness of a recycled composite aggregate

Recycled concrete aggregate (RCA) is a promising substitute for natural aggregates and the reuse of this demolished material would benefit the construction projects both economically and environmentally. A difficulty associated with the prediction of the behavior of RCA is because of its multi-composition which is linked to the grain size in consideration. In this study, a comprehensive laboratory testing program is conducted on different fractions of RCA for which the ratio of silicon over calcium increases for the coarser fractions due to the limitation of the cement mortar inclusion as the mean size increases. The study incorporates bender/extender element tests capturing small-strain constrained moduli, Young’s moduli and Poisson’s ratio of RCA fractions with different mean grain size and grain size distribution. For the uniform RCA fractions, the results showed that during isotropic compression, the specimens had a clear dependency of their dynamic properties on mean grain size. For the better graded specimens, it was shown that their behavior was dominated to some extend by the finer fraction they were composed rather than being affected equally by the different fractions they consisted of. The results also highlighted the sensitivity of the behavior of the samples to the over-consolidation stress history. For RCA, a multi-composition material, the grain size has a dominant role on the modulus – pressure relationship as well as the sensitivity of material behavior to stress history and these observations must be considered in the analysis of geo-structures where RCA is used as construction material.

A Designer’s Approach for Estimation of Nuclear‐Air‐Blast‐Induced Ground Motion

A reliable estimate of free‐field ground displacement induced by nuclear‐air‐blast is required for design of underground strategic structures. A generalized pseudostatic formulation is proposed to estimate nuclear‐air‐blast‐induced ground displacement that takes into account nonlinear stress‐strain behaviour of geomaterials, stress‐dependent wave propagation velocity, and stress wave attenuation. This proposed formulation is utilized to develop a closed‐form solution for linearly decaying blast load applied on a layered ground medium with bilinear hysteretic behaviour. Parametric studies of closed‐form solution indicated that selection of appropriate constrained modulus consistent with the overpressure is necessary for an accurate estimation of peak ground displacement. Stress wave attenuation affects the computed displacement under low overpressure, and stress‐dependent wave velocity affects mainly the occurrence time of peak displacement and not its magnitude. Further, peak displacements are estimated using the proposed model as well as the UFC manual and compared against the field data of atmospheric nuclear test carried out at Nevada test site. It is found that the proposed model is in good agreement with field data, whereas the UFC manual significantly underestimates the peak ground displacements under higher overpressures.