Sandy Gravel Research Articles

Optimization schemes for deep foundation pit dewatering under complicated hydrogeological conditions using MODFLOW-USG

The design and optimization of the dewatering scheme for deep foundation pits in a highly permeable heterogeneous layer are critical to protect water resources, control subsidence and mitigate environmental impacts. Numerical simulation is an important and sometimes the only tool in the design of dewatering schemes, especially when the dewatering projects are planned under complex hydrogeological conditions with limited data. The open excavation method was chosen for a project to drain a deep foundation pit (35–44 m) in an upland river valley landscape. Quaternary alluvial deposits (129.0 m thick) are generally distributed in the riverbed and the overburden consists mainly of alluvial-diluvial sandy gravel cobbles, clayey soils, sandy clay, and silty fine sand, making the study area very heterogeneous. There may be water inrush from foundation pit, uneven subsidence and deformation due to the uneven structure of the sand and slope stability. MODFLOW-USG (Unstructured Grid) and Subsidence and Aquifer-System Compaction (SUB) Package were used to create a coupled 3-D groundwater flow-subsidence numerical model for foundation pit dewatering. MODFLOW-USG provides greater flexibility in the design of the grid to achieve a high degree of accuracy in numerical simulation, while effectively reduces computational costs. A combination of waterproof curtain and a partial penetrating well was proposed for lowering the groundwater table. The optimized dewatering scheme with a curtain depth of 60 m and a hydraulic conductivity of 0.00518 m/d, and four rows of dewatering wells with an equal row spacing of 40 m, well depth of 50 m, and well spacing of 12.5 m in each row can meet the dewatering requirements with minimum groundwater discharge in the scenarios. The numerical simulation of this study provides a powerful and useful tool for dewatering and subsidence control of deep foundation pit under complex hydrogeological conditions.

Impact of the Three Gorges Dam on riverbed scour and siltation of the middle reaches of the Yangtze River

AbstractThis study investigated the influence of the Three Gorges Dam (TGD) on the evolution of nearby channels in the Yangtze River (Changjiang River) system in order to better understand the environmental impact of large‐scale reservoir operations. From 2003 to 2017, the amounts of runoff and sediment transport in the Yangtze River were reduced by 3.3–14.5% and 67.8–92.7%, respectively, relative to 1955–2002 before the TGD was operational. Topographic measurements of the middle reaches (Yichang to Hukou) of the Yangtze River were analyzed from 1975 to 2017, during which time the cumulative erosion of the flood channel was 22.78 × 108 m3, and the dry channel accounted for 90.3% of the erosion. Following commissioning of the TGD, the scouring intensity of the sandy gravel section near the dam initially increased then decreased, whereas the scouring intensity of sandy sections away from the dam continued to increase. Beaches on convex banks of curved sections were scoured, and deep channels on concave banks became silted. In braided sections, the braids tended to shrink, and the diversion ratio of the main branch during dry seasons reduced, resulting in frequent branch alternation. Compared to changes in the downstream river channels of other large reservoirs worldwide, scouring from the TGD is extensive. The findings of this study are significant for river channel regulation and waterway planning in the Yangtze River and worldwide.

Evaluation Indices and Design Method to Determine the Rolling Density of Dam Shell Sandy Gravel Material

AbstractSandy gravel dams with clay core walls are a widely used dam type, and the rolling density of sandy gravel material is evaluated by the relative density Dr. Consequently, designing the opti...

Occurrence and distribution of Pharmaceuticals and Personal Care Products (PPCPs) in wastewater related riverbank groundwater

Pharmaceutical and personal care products (PPCPs) are among the most frequently reported groups of emerging contaminants in groundwater worldwide. PPCPs in rivers may infiltrate into groundwater through hydraulic exchange and potentially threaten drinking water safety and human health. In the present study, the occurrence and distribution of nine PPCPs in riverbank groundwater and adjacent rivers (distance up to 113 m) were investigated at four sites with different lithological features and permeabilities of aquifers in a city in North China. Seven of nine PPCPs were detectable in groundwater, ranging from <LOQ (limit of quantification) to 128 ng/L. N,N-diethyl-meta-toluamide (DEET), carbamazepine, and caffeine had the highest detection frequencies (>90%). The concentrations and major compounds in river water varied with the sampling location and water system distribution, resulting in distinct compositions of PPCPs in the groundwater at each site along with different lithology and hydrological conditions. The spatial distribution of PPCPs in riverbank groundwater was affected by the hydraulic connection between the groundwater and river and the lithology of aquifers. Direct hydraulic connection of a fine sand aquifer to the adjacent river caused a decrease in PPCPs with increasing distance. The results also suggested that sandy gravel aquifers had a lower capacity to attenuate PPCPs compared to that of fine sand. Significant correlations between PPCP concentrations and thirteen physicochemical factors of groundwater were discovered, including nitrate, potassium, and manganese. Overall, this study provides important evidence on the role of lithology and hydrological conditions on the composition, distribution, and influential physicochemical factors of PPCPs in riverbank groundwater.

Groundwater Characterization and Salinity Intrusion Studies using Electrical Resistivity Survey (ERS)-Winder, Balochistan, Pakistan

The groundwater resources have always been explored for its utilization in domestic and agriculture purposes. In this study, Winder area in Balochistan which is along the coast of Offshore Indus Basin has been explored using electrical resistivity method for deeper understanding of hydrogeological and hydrogeophysical conditions. Schlumberger electrode arrays have been used to acquire vertical electrical sounding data for 23 different sites in this area. The field data were calibrated with theoretical curves during processing using software with graphical interface. The true resistivities, depths, thicknesses, aquifer attributes, soil type and groundwater quality has been extracted from the processed data. Pseudo-sections and geo-electrical lithology sections have been generated for lateral distribution of hydrogeological settings. Furthermore, Dar-zarrouk parameters calculations have been made and 3D surfaces generated at 30m and 60 m depth for transverse resistance (T), longitudinal conductance (S) and anisotropy (λ) plotted for resistivity distribution and coastal salinity intrusion analysis. The soundings results depict five layers mainly composed of silty sand, sandy clay, sand, and sandy gravel and the depth ranges from 0-110m. The interpretation illustrates that freshwater unconfined aquifer are present in the quaternary sand and sandy gravel deposits. The water table is at shallow depth along the river and deeper in northeast and away from Winder river. The resistivity ranges 29-1091 Ωm in layer-3 interpreted as saturated zone. The approximate range of water table is 19-30 m. The higher value of T greater than 10000 shows fresh water and low value 8200 for salinity intrusion in southwest toward sea.

Soil Moisture Retention Characteristics Of Saprock From The Weathering Profile Over A Biotite-Muscovite Granite In Peninsular Malaysia

The weathering profile at the slope cut near Km 16 of the Kuala Lumpur - Ipoh trunk road can be differentiated into an upper, 11.8 m thick pedological soil (zone I) and a lower, 31.9 m thick saprock (zone II) comprising silty sandy gravels that distinctly preserve the minerals, textures and structures of the original granite. In order to investigate the influence of particle size distributions on soil moisture retention characteristics, saprock samples were collected at depths of 26.53 m (Sample A), 31.29 m (Sample B) and 41.93 m (Sample C). Samples A and B, with porosities of 37%, comprise 33% gravel, 27% sand, 22% silt and 18% clay, and 31% gravel, 24% sand, 25% silt and 22% clay, respectively. Sample C with a porosity of 44% consists of 24% gravel, 28% sand, 38% silt and 10% clay. Tests with the pressure plate method show increasing suctions from 0 kPa through 0.98 kPa and 9.8 kPa to 33 kPa and 1,500 kPa to result in gravimetric soil moisture retentions of 31.9% through 28.6% and 23.3% to 16.9% and 6.8% in sample A, of 32.1% through 24.9% and 21.5% to 17.8% and 7.4% in sample B, and of 31.5% through 30.3% and 27.30% to 23.5% and 9.5% in sample C. Regression analyses of gravel, sand and clay contents plotted against moisture contents retained at high suctions (33 kPa and 1,500 kPa) yield negative trends with variable correlation coefficients (R2), though plots involving silt contents yield positive trends with large correlation coefficients (R2 &gt;0.9966). It is concluded that adsorption of water on surfaces of silt sized particles (of mainly sericite derived from weathering of feldspars) that gives rise to the retention of soil moisture in saprock.

Unconventional and Simplified Approach towards Unpaved Roads: Application of Geosynthetics

Abstract: A field trial was carried out to investigate the performance of different unconventional geosynthetic materials in unpaved road construction over soft ground.The test site comprises of 25 m long, by 3 m wide test sections, built on a subgrade of undrained shear strength approximately 45 kPa . One isunreinforced and serves as a control section in the study, three sections includea geotextile, and one includes a geogrid. Each test section incorporated avariable thickness of sandy gravel base course material, between25 and 45 cmthick. They were loaded in sequence by a vehicle of standard axle load.Performance of the test sections was evaluated from measurements of rut depth, base course thickness, base course deformations, geosynthetic strain, and deformed profile of the geosynthetic, with increasing number of vehicle passes.The four geosynthetic materials used exhibited a broad range of stiffness and material properties ,but the general performance of the four reinforced sections was similar on the base course layers. On contrary thinner subgrades showed a significant difference between the geosynthetics Keywords: Geo-synthetic materials, geo-textile, geo-grid, unpaved road.

Measurement of Seafloor Acoustic Backscatter Angular Dependence at 150 kHz Using a Multibeam Echosounder

Acoustic seafloor measurements with multibeam echosounders (MBESs) are currently often used for submarine habitat mapping, but the MBESs are usually not acoustically calibrated for backscattering strength (BBS) and cannot be used to infer absolute seafloor angular dependence. We present a study outlining the calibration and showing absolute backscattering strength values measured at a frequency of 150 kHz at around 10–20 m water depth. After recording bathymetry, the co-registered backscattering strength was corrected for true incidence and footprint reverberation area on a rough and tilted seafloor. Finally, absolute backscattering strength angular response curves (ARCs) for several seafloor types were constructed after applying sonar backscattering strength calibration and specific water column absorption for 150 kHz correction. Thus, we inferred specific 150 kHz angular backscattering responses that can discriminate among very fine sand, sandy gravel, and gravelly sand, as well as between bare boulders and boulders partially overgrown by red algae, which was validated by video ground-truthing. In addition, we provide backscatter mosaics using our algorithm (BBS-Coder) to correct the angle varying gain (AVG). The results of the work are compared and discussed with the published results of BBS measurements in the 100–400 kHz frequency range. The presented results are valuable in extending the very sparse angular response curves gathered so far and could contribute to a better understanding of the dependence of backscattering on the type of bottom habitat and improve their acoustic classification.

Disturbance Process of Sandy Gravel Stratum Caused by Shield Tunneling and Ground Settlement Analysis

This paper analyzed the earth pressure, pore pressure, and surface settlement of the Luoyang urban rail transit tunnel in a sandy gravel stratum (Henan Province, China) under different burial depths by using field measurement methods. The results showed that the earth pressure as well as pore pressure of the soil layer above the working surface increased sharply and reached their maximum values when the cutter head of the shield gradually crossed the working surface. During the completion of synchronous grouting, the earth pressure and pore pressure increased slightly; when shield tunneling passed through the working surface, the earth pressure is smaller than the original earth pressure due to the unloading effect. The surface settlement curve above the tunnel took on a “V” shape after the completion of the left-side tunnel excavation, conforming to the normal distribution pattern. The surface settlement curve above the two tunnels took on a “W” shape after the completion of the right-side tunnel excavation, which is in good agreement with the proposed theoretical calculations. The findings of this study can help for better understanding the control of safety risk during shield construction.

A systematic framework for DEM study of realistic gravel-sand mixture from particle recognition to macro- and micro-mechanical analysis

Reproducing realistic particle shape is vital for discrete modeling of granular construction materials, such as sands and gravels, which are widely used foundation soils in civil engineering. The existing algorithms used to determine particle shapes from the raw images of construction materials are very limited, especially when dealing with binary mixtures, such as sandy gravel. To address this issue, this study aims to develop a systematic framework for realistic simulation of the gravel-sand mixture based on deep-learning-enhanced discrete element method (DEM). An efficient and convenient method is proposed to quickly identify particle contour and establish particle shape libraries based on a combination of YOLOv5 and U-Net algorithms. Furthermore, DEM-based biaxial compression tests are conducted on two groups of gravel-sand mixture based on the acquired realistic coarse and fine particle shapes. The influences of coarse particle shapes and fine sand content on the macroscopic and microscopic behaviors of gravel-sand mixtures are quantitatively and comparatively studied. The proposed framework for deep-learning-enhanced particle shape acquisition and realistic DEM simulation will provide researchers with more convincing physics-based insights into granular mechanics and has the potential to be extended into 3D to benefit practical problems.

Imaging indigenous sacred sites: A tale of clay, silt, and sand

When studying indigenous sites, especially sacred sites such as burials, the needs and wishes of the indigenous people are paramount; the site integrity must be respected, and the site must be left intact and undisturbed. Noninvasive, nondestructive geophysical imaging is well suited to such investigations, but suspicion within indigenous communities because of past transgressions is a barrier to widespread use; skepticism is not uncommon, but we have always managed to convince skeptics. We have developed an overview of results from 10 Māori (the indigenous peoples of New Zealand) sites in the South Island of New Zealand: one historic burial site, six modern burial sites that also had historical use, one historic battle site, one prehistoric site that may have been a burial site, and one prehistoric site used for food storage that was tapu (sacred). Our approach was to let them ask us to delineate areas of importance, for example, old burial sites. There are, naturally, processes and protocols, cultural and technical, that we followed. The sites comprised a range of lithologies and soil types: one site where clay soil overlays limestone, five sites where loess (airborne silt) overlays basalt, one set of inland silty soil sites, one site on peat soils overlying sandy gravels, and two sites in coastal sands. The geophysical responses of the sites cluster into three groups: Horizontal loop electromagnetic (HLEM) and magnetic field methods worked well for the clay soil site, and once the effects of the conductive clay response were removed by filtering, ground-penetrating radar (GPR) worked well. HLEM and magnetic results were good to equivocal on the silty and peaty sites, whereas GPR excelled at delineating anomalous features, particularly burials, which yielded clear characteristic diffraction responses. Finally, results for coastal sand sites were disappointing. Such sites appear to be too dynamic to yield useful results.

Application of Laser Scanning to Assess the Roughness of the Diaphragm Wall for the Estimation of Earth Pressure.

The correct estimation of earth pressure is important for the design of earth retaining structures and depends, among others, on the surface morphology of retaining structures. The diaphragm wall created as a protection of a deep excavation located in an urbanized area was selected as a research object. Terrestrial Laser Scanning (TLS) was used for the investigation of the unique surface (in real-world dimension) obtained by tremieying the concrete in different soil layers. An original and innovative procedure for concrete surface description was developed, which includes steps from the TLS measurement to the determination of the roughness parameters. The tested samples from anthropogenic soil, medium sand, and sandy gravel, map the real diaphragm wall surface. The surface roughness parameters in different soil layers were compared with the reference surface obtained by cast against steel formwork. The following parameters: Sa, Sdr, and Vmc are indicated as being the most useful in numerical description of the concrete surface type and in allowing the determination of the soil surface friction. The novelty of this study is the estimation of the parameter δ (friction angle between the retaining wall surface and the soil), which is, among others, a function of the wall surface roughness. The influence of the type of surface on earth pressure are generally recognized in laboratory tests. Based on the estimated in situ values of δ, the more reliable active and passive pressure coefficients Ka, Kp were calculated for the tested soil layers. The conducted study has a practical significance for designing of retaining construction and makes progress in determination of surface roughness required in Eurocode 7.

Innovation structures of very lean roller compacted concrete dams

Over the past 20 years, rolled compacted concrete (RCC) dams have continued to be built in many countries because of their technical and economic advantages over conventional dams of vibrating concrete and embankment dams. The aim of this study is the development of new structural and technological solutions in RCC dams in order to reduce the consumption of cement and expand their use on non-rock foundations, which will allow them to successfully compete with concrete face rockfill dams. The numerical analyses of static and seismic stress-strain state (SST) of gravitational dams in roller compacted very lean concrete dams have been made, as well as their stability, strength and cost have been assessed. For rock and dense sandy-gravel foundations the most economical is the concrete face rockfill dam and symmetrical RCC dam of very lean concrete with bases (0.5-0.7) of both slopes and outer zones of conventional concrete and central zone of rockfill strengthened by cement-ash mortar. Taking into account that the cost of diversion and spillway tunnels for very lean RCC dam will be less and the construction period - shorter than for the concrete face rockfill dam, it can be concluded that variant of symmetrical RCC dam of very lean concrete is the technically and economically effective. Symmetrical RCC dams of very lean concrete with 1V/(0.5-0.7)H slopes have more seismic resistance and technical and economic efficiency as compared with conventional gravitational RCC dams and other types of dams. These dams up to 200 m high can be built on rock foundations and up to 100 m high - on dense sandy gravel foundations.

A levee breach induced by internal erosion in Western Australia

This case study presents a levee breach induced by piping erosion under cyclonic conditions in 2019. The levee is a 2.5 m-high, 500 m-long, mass earth-fill embankment; with no cutoff trench, core or ancillary structures. Located near Port Hedland on the north coast of Western Australia, its purpose is diversionary: to redirect cyclonic surface water away from the nearby Great Northern Highway. The levee was founded directly on alluvium in 1987; it is formed of locally sourced clayey sandy gravel. In 2003, the levee was partially excavated to enable the placement of a buried pipeline through the levee. Following a cyclonic event in 2019, a 27 m length of the levee breached, resulting in significant scour of the foundation and downstream soil. A site visit and investigation were conducted shortly thereafter, where in situ testing and laboratory soil tests on the levee and foundation materials were conducted. Analysis of the site observations and laboratory testing data led to the probable failure mechanism being theorized as having been initiated within the foundation by piping erosion within sand-rich beds of alluvium. The large quantity of water ponding upstream of the levee then caused a progressive washout and breach of the levee. Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

Coupled hydro-mechanical influence on hydraulic conductivity of well-graded sandy gravel

Coupled hydro-mechanical influence on hydraulic conductivity of well-graded sandy gravel

A LABORATORY MODEL FOR THE ADSORPTION AND LOSS OF THE SULFATE TRANSPORT IN MULTI POROUS MEDIA OF SOIL

Development of industries and agriculture, salts, especially sulfates, used in many industries, such as fertilizers and pesticides, have become one of the most common problems. In this paper, a laboratory model was established to study the sulfate-contaminated transport process. Four samples of porous media contain the same pollutant, sandy soil, sandy gravel soil, agricultural (organic) soil, and calcareous soil. Where a pollutant is pumped at a concentration of 280 mg/l through a system consisting of a tube of length 4 meters and 8 cm thickness and distributed in the soil Each type is one meter. The results showed that all types of soils, except organic, had leaching or loss of sulfates from the soil and dissolving them with a soil solution. The transfer of pollutants from soil to the solution may reach between 50 to 300 mg/l per meter, while organic soil showed the ability to Absorption up to 100 mg/L per meter. However, it was found that organic soil contains the largest amount of sulfate and was able to adsorption, and it was found that bacterial activity has a role in reducing sulfate in organic soil and thus returning the soil to adsorption after a certain time of saturation process.

Preservation and distribution of detrital clay coats in a modern estuarine heterolithic point bar in the Gironde estuary (Bordeaux, France)

ABSTRACT Estuaries provide an excellent depositional environment to study the interaction between minerals (clays, quartz sands…) and biofilms. The estuary bottom is largely covered by biofilms that impact sediment stability, the mud and clay-coat content in sands, and sedimentary-structure stability, thus influencing sandstone properties during burial. Although numerous oil, gas, and geothermal reservoirs are exploited in estuarine heterolithic point bars, many questions remain about the origin of reservoir properties and heterogeneities in these sedimentary bodies. In order to better understand the sedimentary and microbiologic processes in estuarine systems and to better predict the reservoir quality of estuarine sandstones, this study characterizes a modern heterolithic point bar located in the Garonne estuarine channel at various scales, ranging from the microscopic (thin section) to the macroscopic (core) scale. Three piston cores 4.5 to 6.8 m long were drilled in the Bordeaux North Point Bar. Three main facies were identified in these cores: 1) sandy gravel, 2) heterolithic, medium-grained sand dunes, and 3) thin heterolithic, fine-grained sand beds with mud drapes. The sands are classified as lithic arkoses to feldspathic litharenites. Detrital clay grain coats, which at deep burial depths are transformed to permeability preserving authigenic chlorite coatings, are observed from the base to the top of the point bar. These detrital clay grain coats are mainly composed of smectite, illite, kaolinite, and chlorite, intermixed with other components, such as diatoms or pyrite. Biofilms of exopolymeric substances (EPSs), mostly produced by diatoms, are believed to control the adhesion of the clay coats to the surface of sand grains. Quantification by thin section shows that on average about 30% of the sands are coated in the point bar. The proportion of clay-coated grains appears to be independent of facies. Radiocarbon age dating measured on organic matter points to significant vertical mixing, highlighting the significance of erosion and redeposition. The activities of 137Cs and 210Pb indicate a vertical sedimentation rate of ca. 0.02 m.yr–1 in the muddy chute channel. These ages, coupled to historical maps, suggest that the present-day point bar has developed over the last 300 years with a vertical sedimentation rate ranging from 0.015 to 0.036 m.y–1 and a lateral migration rate of about 1 m.y–1. The combination of sedimentary geology, thin-section petrography, and mineralogy at high spatial and temporal resolutions highlights the potential of this study area as a modern analogue for ancient tidally influenced point-bar deposits associated with clay coatings.

Plio-Pleistocene paleoenvironmental evolution of the intermontane Humahuaca Basin, southern Central Andes

Sedimentary records of Plio-Pleistocene intermontane basins of the Eastern Cordillera and the adjacent Puna Plateau in the Central Andes of NW Argentina (hinterland basins) are important geological archives that provide spatiotemporal insights into regional tectonism, the uplift history of basin-bounding mountain ranges, and associated depositional and paleoenvironmental changes. Here, we reconstruct the Plio-Pleistocene evolution of the intermontane Humahuaca Basin based on the study of depositional systems, unconformities, accumulation rates, depositional patterns, U–Pb geochronology, magnetostratigraphy, and sediment provenance of the Uquía Formation – a ca. 4.8–1.5-My-old sedimentary basin record consisting of a 100–400 m thick fining-upward stack of conglomerates, sandstones, and siltstones with intercalated volcanic tuffs. The sedimentary facies of the Uquía Formation comprise debris flow, deep sandy gravel braided alluvial fan deposits, sheetflood dominated, floodplains, and shallow ephemeral lake deposits. Facies characteristics and δ18O and δ13C values from pedogenic and palustrine carbonates indicate freshwater lacustrine conditions at the base and evaporative conditions towards the top of the Uquía Formation (ca. 2.3 Ma). During the deposition of the Uquía Formation, the Humahuaca Basin was already bounded by uplifted mountain ranges: (a) the Sierra Alta to the west, which experienced early uplift during the middle Eocene and increased exhumation from about 15 to 10 Ma; and (b) the Aparzo and Tilcara ranges to the east, whose deformation and uplift began about 15–10 Ma and culminated in the structural and fluvial separation of the Humahuaca Basin from the foreland by ca. 4.8 Ma in the center and by about 4.2 Ma in the southern sector of the basin. This is supported by variable unroofing patterns, the paleoenvironmental evolution, deposition of sheetflood dominated alluvial fans, and lacustrine deposits.

Upscaling Transport of Bacillus subtilis Endospores and Coliphage phiX174 in Heterogeneous Porous Media from the Column to the Field Scale.

Groundwater contamination and transport of viruses and bacteria in aquifers are a major concern worldwide. To ascertain the ability of these aquifers to remove pathogens, tracer tests with microbial surrogates are carried out. These tests are laborious and may require special permits, and therefore, column tests are often done instead. Unfortunately, results from column tests tend to grossly overestimate removal rates when compared to the field scale, which can lead to an underestimation of groundwater contamination risks. Scale is an important consideration when examining pathogen transport through porous media, as pathogen removal is rarely a linear process. In this study, field tests were carried out with endospores of Bacillus subtilis and coliphage phiX174 over a distance of 25 m in an alluvial gravel aquifer near Vienna, Austria. The sandy gravel material from the field site was also used in column tests with the same tracers. Both attachment-detachment and colloid filtration theory were used to model these tests, as well as log-removal rates per meter. The results show that the spatial removal rate (log/m) is approximately 2 orders of magnitude higher on the column scale, when compared to the field. A comparison with the literature showed a correlation between the heterogeneity of the porous media and the difference in removal rates between the column and field scale.

Experimental-numerical study on the structural failure of concrete sewer pipes

The structural failure of round and egg-shaped sewer pipes is investigated by means of laboratory experiments and finite element method analyses. Two different round pipes are considered, which have an inner diameter of 400 mm and 500 mm, and are respectively referred to as R400 and R500 sewer pipes. The egg-shaped pipe considered in this study has a horizontal inner diameter of 400 mm and a vertical inner diameter of 600 mm, and is labeled as the E400/600 sewer pipe. Sewer pipes with these dimensions are most commonly used in the Netherlands. In full-scale experimental tests the sewer pipe specimens are subjected to biaxial loading, whereby the horizontal pressure loading is set equal to 1/3 times the vertical pressure loading. This loading condition is representative of a sewer pipe embedded in a well-graded sandy gravel and subjected to neutral horizontal earth pressure. Apart from the global load–displacement behaviour, the local strain response is measured at various locations, which indicates how the applied load is distributed across the sewer pipe. The fracture pattern at catastrophic failure is recorded by means of cameras placed at the front side of the pipe specimen. The round pipes fail under the development of 4 distinctive failure cracks, which are located at the top and bottom of the sewer pipe, and halfway the left and right sides. The egg-shaped sewer pipes also fail under the development of 4 failure cracks, which emerge at the top and bottom of the pipe, and at the top-left and top-right sides. The round R500 pipe fails at the lowest ultimate failure load, which is, respectively, a factor of 1.16 and 2.25 smaller than the ultimate failure loads of the round R400 pipe and the egg-shaped E400/600 pipe. The FEM models of the round and egg-shaped pipes accurately predict both the failure response and the fracture pattern measured in the experiments. Accordingly, the FEM model of the round R400 sewer pipe is used to analyse the sensitivity of the overall failure response of the sewer pipe to various parameters, which are the load contact area, the ratio between the applied horizontal and vertical loads, the wall thickness of the sewer pipe, and the tensile strength, mode I toughness and Young’s modulus of the concrete. The variation of these parameters mimics how the load bearing capacity of a sewer pipe decreases under the effects of soil erosion, changes in lateral earth pressure, biochemical degradation, and ageing. The knowledge obtained from the experimental–numerical study may support the decision making process on maintenance and replacement of sewer systems.