The issue of geotechnical hazards induced by excavation in soft soil areas has become increasingly prominent. However, the retaining structure and surface settlement deformation creep spatial effect sequence are not fully considered where only elastic–plastic is used design. To understand spatiotemporal effects excavation-induced pits, a case study was performed with Huaxi Park Station Suzhou Metro Line S1, Jiangsu Province, China, as an example. Field monitoring conducted, three-dimensional...

The drawdown outside of a deep foundation pit has to be controlled during excavation. However, the vertical curtain cannot cutoff and thick confined aquifer In this study, microbial-induced carbonate precipitation (MICP) horizontal seepage reducing body (HSRB) was proposed control combined with partially penetrating curtain. MICP HSRB is formed by using field generated recharge wells drive migration Sporosarcina pasteurii solution, stationary cementation solution into aquifer. each...

During underground space exploitation in the urbanization process, numerous foundation pits were constructed where a diaphragm wall was often used as retaining structure and waterproof curtain. Due to complicated engineering geological conditions or improper construction, walls joints exhibit quality defects. Groundwater leaked from these defects during excavation, endangering safety of pit surrounding facilities. The current leakage identification performed by artificial visual detection,...

Ridge slopes often occur in highway or railway engineering. The initial stress distribution of a ridge slope is important for the original and an excavation slope. In this paper, wire-frame model was established. Numerical simulations on 3D stability analysis were performed using strength reduction method based unified theory. influences ridgeline dip angle α, flank β, height H deformation failure mode analyzed. When α small, cracking easily occurred at front edge area near line. large,...

The potential deformation and failure of a slope with typical 3D shapes involve characteristics, such that these factors cannot be simulated using 2D methods. If characteristics are not considered in expressway monitoring, an excessive number monitoring points may arranged the stable/safe part, whereas insufficient unstable/dangerous part. In this study, Lijiazhai Shicheng-Ji'an Expressway Jiangxi Province, China were analyzed by numerical simulations strength reduction method. surface...

The construction of an island airport on a coral reef will inevitably encounter wave, tidal and aircraft takeoff landing loads. To study the dynamic response sand under these loads, 1:50 laboratory model test was conducted with Meiji Reef Airport as engineering background. studied pore water pressure characteristics strata beneath runway wave loads different heights, impact cyclic loading times. Additionally, displacement times were also studied. results show that decreases increasing...

The multi-aquifer and multi-aquitard system (MAMA) is a typical geological structure in deltas. Thus, the risks challenges to settlement control environmental protection are increased when demand for underground space extends deeper strata. In this study, dewatering-induced stratified MAMA divided into three stages according whether overlying aquitard coupled with groundwater seepage. Subsequently, large physical model tests were carried out. Seepage compression strata come after confined...

Ultra-shallow-buried and large-span double-arch tunnels face complex risks during construction. The risk sources are hidden, complicated, diverse. dynamic assessment problem cannot be solved satisfactorily by using the static method as an insufficient amount of research has been conducted. land part Xiamen Haicang tunnel was selected background for ultra-shallow-buried construction process divided into five stages: pre-construction preparation; ground surrounding rock reinforcement; pilot...

The construction of island airports on coral reefs inevitably encounters the impact load aircraft takeoff and landing. However, previous studies have not presented a detailed description dynamic response sand beneath runways reclamation under load. In current study, Mischief Reef Airport in Nansha Islands, China, was selected as background. pore water pressure strain characteristics reshaped loads with different stress amplitudes vibration frequencies were studied using triaxial tests....

Taking the Zigaojian tunnel, Hangzhou–Huangshan high-speed railway, China, as background, rock mass structure effect on smooth blasting quality was studied. Four structures were determined basis of information collected tunnel site. Smooth finite element models established using LS-DYNA. The accuracy numerical calculation model verified by comparing overbreak and underbreak between simulation monitoring. Orthogonal test used to study through single factor main analysis methods. With decrease...

Constructing a large section bifurcated small clear distance tunnel poses significant challenges due to its and distance, complex overlapping construction steps, unsynchronized excavation support processes, disturbance of surrounding rock caused by blasting. Timely effective monitoring is crucial ensure safety quality. However, traditional methods are unable fully satisfy requirements realize real-time monitoring. Therefore, this study proposes an automatic control method for leverage the...

Groundwater level has to be lowered during deep excavation. A vertical curtain is usually adopted control the drawdown inside and outside a foundation pit in built-up area. However, cost working difficulty increases substantially with rise depth of curtains. In manuscript, man-made horizontal seepage reducing body (HSRB) was introduced shorten drawdown. With No. 4 shaft Guangyuan Project, Shanghai as background, HSRB proposed dewatering. Microbially induced carbonate precipitation grouting...

Abstract Leakage in operating tunnels is a serious problem during stage. In order to realize non-destructive detection of leakage an shield tunnel, optical fiber temperature measurement method based on Raman scattering and infrared thermal imaging technology developed. The working principle monitoring with Distributed Fiber Optic Temperature Sensor (DTS) combined time domain reflectometry (OTDR) are introduced. distributed field realized typical tunnel. Infrared imager used perform the area,...

Leakage in the diaphragm wall is difficult to detect deep foundation pits. In this study, conceptual model of active and passive thermal leak detection methods was proposed according occurrence temperature field anomalies caused by seepage. Experiments were performed using a heating system an optical fiber measurement verify leakage systems. Numerical simulations understand mechanism detecting method. Results indicated that cable could low-temperature anomaly detection. The arrangement...

Microbial-induced calcite precipitation (MICP) is an environmentally friendly alternative to conventional chemical grouting for enhancing geotechnical properties in soils. Certain particle size distribution soils can be effectively improved through MICP enhance integration. Understanding the mechanisms and applicability of on with different sizes distributions prior its implementation crucial. The previous studies enhanced soil focus seismic liquefaction. Whether method used other...

<title>Abstract</title> Intermediate principal stress (IPS) may influence the stability of a slope under three-dimensional (3D) failure modes. However, IPS is seldom considered in evaluation. In this study, 3D and mode ridge analyzed by considering IPS. The mathematical model double-shear unified strength theory was established using UMAT subroutine Abaqus software. on deformation damage modes homogeneous studied reduction method. results calculated Mohr-Coulomb criterion were very close to...

Using a soil improvement biotechnology based on microbial-induced carbonate precipitation (MICP) to form horizontal water barrier in foundation pit dewatering can not only achieve good control effect, but also the cost and obtain economic environmental benefits. In this study, taking Shanghai layer ⑨ sand as research object, solution injected into by MICP grouting technology includes bacterial (Sporosarcina pasteurii) cementation (urea CaCl2 solution). The migration mechanism of groundwater...

Large section tunnels have huge excavation spans, complex procedures, mutual influence among various multiple disturbances of the surrounding rock, and discontinuous connection linings under different which bring great difficulties to their construction. The Caijianwei Mountain No. 2 tunnel Xiamen Haicang Evacuate-channel project in China belongs a super large tunnel. tunnel’s maximum span reaches 30.52 m, area 421.73 m2. Its sequence, timing second primary lining support, temporary support...

Abstract Groundwater level has to be lowered during deep excavation. A vertical curtain is usually adopted control the drawdown both inside and outside a foundation pit in built-up area. However, cost working difficulty increases substantially with increasing depth of curtains. In manuscript, kind man-made horizontal seepage reducing body (HSRB) was introduced shorten drawdown. With No. 4 shaft Guangyuan Project, Shanghai as background, HSRB proposed dewatering. Microbially induced carbonate...