Tunnel Site Research Articles

P-phenylenediamines (PPDs) and 6PPD-quinone in tunnel PM2.5: From the perspective of characterization, emission factors, and health risks

P-phenylenediamines (PPDs) and a quinone derivative (6PPD-Q), as antioxidants added to tires, can inevitably enter into the environment during tire wear emission, posing potential health and ecological risks. However, investigation on their pollution characteristics in PM2.5 is still lacking, especially for high-pollution scenarios, such as tunnels. Herein, we investigated the pollution characteristics and emission factors, as well as the correlation analysis and daily intakes of PM2.5-bound PPDs and 6PPD-Q in tunnel. The results indicated heavy PPDs and 6PPD-Q pollution were observed in tunnel PM2.5, with the concentration at the two tunnel sites being 3.83 and 8.73 times higher than those at the urban site, respectively. PPDs were negatively correlated to relative humidity and positively to temperature. Emission factors of 6PPD and 6PPD-Q were 3013.54 and 1466.67 ng·veh−1·km−1 for large vehicles. PPDs and 6PPD-Q were most harmful to children, and annual exposure dosages at the tunnel sites were 4.64 times higher than those at the urban site. This study conducted a comparison of PPDs and 6PPD-Q in urban and tunnel environments for the first time. Our findings clarified the key factors to reduce the pollution of PPDs in tunnel and supported policy-making for emission reduction of PPDs and 6PPD-Q.

The Effect of Distance between Jet Fans on Gas Transport, Energy Conservation, and Emission Reduction in Long Highway Tunnels

With the rapid development of the national economy, China’s transportation industry is experiencing accelerated development, and, at the same time, the number of long tunnels is constantly increasing. In order to examine the influence of jet fan spacing on gas transport law during the construction of long highway tunnels, this study used the Baima Highway Tunnel in Sichuan as an engineering prototype and established a numerical tunnel ventilation model based on Fluent numerical simulation software. The gas transport characteristics of jet fans in tunnels at different spacings (200 m, 400 m, 600 m, and 800 m) were studied. The results showed that with the increase in jet fan spacing (200 m, 400 m, 600 m, and 800 m), the gas concentration at the tunnel face showed a trend of decreasing and then increasing. Moreover, by analyzing the gas distribution cloud map and the wind flow line diagram, it was determined that the ventilation system effect was the best when the jet fan spacing was 600 m, which met the requirements of a gas concentration of less than 0.5% at the tunnel face and a minimum wind speed of 0.25 m/s. At the same time, according to the optimal spacing for the optimization of the site ventilation system, it was observed that after the ventilation was stabilized (after 600 s), the minimum value of the gas concentration in the left and right tunnel holes diminished from 0.38% to 0.31% and from 0.41% to 0.31%, with rates of reduction of 18.42% and 24.39%, respectively. This indicated that after optimizing the ventilation system at the tunnel site, the concentration significantly decreased compared with before the optimization. Moreover, when the jet fan spacing was 600 m compared with 200 m and 400 m, the annual energy savings were 1900.8 MW·h and 950.4 MW·h, respectively. The research results clarified the optimal layout parameters of jet fans in the Baima Highway Tunnel, providing a reference for the rational layout of jet fans in long-distance tunnels. In addition, the results of this study provide an important theoretical basis for the gas prevention and safe construction of long highway tunnels. Furthermore, this study contributes to research in energy conservation, emission reduction, and sustainable development of energy in the ventilation process during tunnel construction.

Discovery of JAB-3312, a Potent SHP2 Allosteric Inhibitor for Cancer Treatment.

As an oncogenic phosphatase, SHP2 acts as a converging node in the RTK-RAS-MAPK signaling pathway in cancer cells and suppresses antitumor immunity by passing signals downstream of PD-1. Here, we utilized the extra druggable pocket outside the previously identified SHP2 allosteric tunnel site by the (6,5 fused), 6 spirocyclic system. The optimized compound, JAB-3312, exhibited a SHP2 binding Kd of 0.37 nM, SHP2 enzymatic IC50 of 1.9 nM, KYSE-520 antiproliferative IC50 of 7.4 nM and p-ERK inhibitory IC50 of 0.23 nM. For JAB-3312, an oral dose of 1.0 mg/kg QD was sufficient to achieve 95% TGI in KYSE-520 xenograft model of mouse. JAB-3312 was well-tolerated in animal models, and a close correlation was observed between the plasma concentration of JAB-3312 and the p-ERK inhibition in tumors. Currently, JAB-3312 is undergoing clinical trials as a potential anticancer agent.

Efficiency enhancement in Aspergillus niger α-L-rhamnosidase reverse hydrolysis by using a tunnel site rational design strategy

There has been ongoing interest in improving the efficiency of glycoside hydrolase for synthesizing glycoside compounds through protein engineering, given the potential applications of glycoside compounds. In this study, a strategy of modifying the substrate access tunnel was proposed to enhance the efficiency of reverse hydrolysis catalyzed by Aspergillus niger α-L-rhamnosidase. Analysis of the tunnel dynamics identified Tyr299 as a key modifiable residue in the substrate access tunnel. The location of Tyr299 was near the enzyme surface and at the outermost end of the substrate access tunnel, suggested its role in substrate recognition and throughput. Based on the properties of side chains, six mutants were designed and expressed by Pichia pastoris. Compared to WT, the reverse hydrolysis efficiencies of mutants Y299P and Y299W were increased by 21.3 % and 11.1 %, respectively. The calculation results of binding free energy showed that the binding free energy was inversely proportional to the reverse hydrolysis efficiency. Further, when binding free energy levels were comparable, the mutants with shorter side chains displayed a higher reverse hydrolysis efficiency. These results proved that substrate access tunnel modification was an effective method to improve the reverse hydrolysis efficacy of α-L-rhamnosidase and also provided new insights for modifying other glycoside hydrolases.

Effect of varying temperature increases on the microbial community of Pleistocene and Holocene permafrost

The total area covered by permafrost has been continually decreasing over the past decades. This study investigates the effect of various temperature increases on the microbiome of permafrost sampled at the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel site in Fox, Alaska, USA, corresponding to the Holocene (around 8000 years before present (ybp)) and Pleistocene (around 36,000 ybp), respectively. The soil was subjected to two thawing time courses, with temperature increasing from −4 °C to either +4 °C or +25 °C, and total nucleic acid was extracted at each time point. Consistent with previous 16S rRNA amplicon sequencing studies on the Permafrost Tunnel, the Pleistocene was dominated by Clostridia, while the Holocene was mainly composed of Clostridia, Bacteroidia and Alphaproteobacteria at −4 °C. Thawing at +25 °C resulted in divergent microbial profiles for permafrost of both ages, with the Pleistocene becoming more similar to the active layer, while the Holocene was relatively less impacted. Prediction of metabolic function revealed that bacteria from the Holocene permafrost activated degradation pathways upon thawing at +25 °C, while bacteria from the Pleistocene were more involved in amino-acid biosynthesis pathways, suggesting different mechanisms of adaptation.

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

High-temperature smoke generated by tunnel fires is the most important factor causing casualties. To explore the influence of natural wind on fire smoke movement in an extra-long highway tunnel based on the Taihang Mountain Tunnel, the distribution law of natural wind in the tunnel was obtained by on-site monitoring of the meteorological conditions at the tunnel site. A three-dimensional fire dynamics tunnel model considering an inclined shaft smoke exhaust was established, and the influence of natural wind on tunnel temperature distribution, smoke spread and smoke exhaust efficiency was studied. The results show that the natural wind speed of the Taihang Mountain Tunnel is mainly concentrated at 0~3 m/s. The main wind direction of the natural wind on the left tunnel is opposite to the driving direction, and the distribution probability of the main wind direction in each section is 81.27% and 72.15%, respectively. The main wind direction of the right tunnel is the same as the driving direction, and the distribution probability of the main wind direction in each section is 56.78%, 69.73%, 67.32% and 64.65%, respectively. The negative natural wind can inhibit the smoke spread downstream of the smoke exhaust port, but it is not conducive to the smoke exhaust. The positive natural wind promotes the smoke spread to the downstream of the smoke exhaust port, and the larger the natural wind speed, the longer the spread length. Natural wind reduces the smoke exhaust efficiency. For positive or negative natural wind with a guaranteed rate of 70%, the smoke exhaust efficiency is reduced by 27.76% and 15.59%, respectively, compared with the condition without natural wind. The research results can provide a useful reference for the design of fire smoke exhausts and smoke control schemes in extra-long highway tunnels.

Large-scale model test study of the mechanical characteristics on sprayed ECC layer of highway tunnel under confining pressure

As the geological environment of highway tunnels becomes increasinlgy complex, sprayed engineered cementitious composites (ECC) has broad application prospects in the field of highway tunnel support. This study focuses on the shotcrete layer in the initial support of Wulingtou extra-long highway tunnel, the 1:4 scale model test of sprayed ECC layer under confining pressure was prepared. Its mechanical properties and real-time joint monitoring are determined using strain gauges, distributed optical fibers, and cameras. The results show that the maximum confining pressure of the sprayed ECC layer is 0.975 MPa with the maximum displacement of 15.497 cm, which outperforms ordinary shotcrete. The loading process of steel bars and sprayed ECC can be divided into three stages, with the change rate of these three stages showing an ascending trend. The failure mode is ductile, involving normal section, oblique section compression shear failure and bending shear failure. In addition, based on the similarity theory, the real mechanical characteristics of the sprayed ECC layer at the tunnel site can be predicted according to the experimental model.

Sharp needle reconstructs peripheral outflow for patients with malfunctional arteriovenous fistula

Objective To investigate the feasibility and efficacy of combining ultrasound-guided sharp needle technique with percutaneous transluminal angioplasty (PTA) for treating outflow stenosis or dysfunction in arteriovenous fistula (AVF) among hemodialysis patients. Methods From October 2021 to March 2023, patients with occluded or malfunctional fistula veins not amenable to regularly angioplasty were retrospectively enrolled in the study. They underwent ultrasound-guided sharp needle intervention followed by PTA. Data on the location and length between the two veins, technical success, clinical outcomes, and complications were collected. Patency rates post-angioplasty were calculated through Kaplan-Meier analysis. Results A total of 23 patients were included. The mean length of the reconstructed extraluminal segment was 3.18 cm. The sharp needle opening was performed on the basilic vein (60.9%), brachial vein (26.1%), or upper arm cephalic vein (13%) to create outflow channels. Postoperatively, all cases presented with mild subcutaneous hematomas around the tunneling site and minor diffuse bleeding. The immediate patency rate for the internal fistulas was 100%, with 3-month, 6-month, and 12-month patency rates at 91.3%, 78.3%, and 43.5%, respectively. Conclusion Sharp needle technology merged with PTA presents an effective and secure minimally invasive method for reconstructing the outflow tract, offering a new solution for recanalizing high-pressure or occluded fistulas.

Optimization of Blasting Parameters Considering Both Vibration Reduction and Profile Control: A Case Study in a Mountain Hard Rock Tunnel

The number of excavated tunnels is increasing day by day, and the corresponding engineering scale is also getting increasing. Safe, efficient, and economically beneficial tunnel construction methods are indispensable in the process of crossing mountains and steep ridges in the southwest region. However, behind the improvement of transportation infrastructure in Southwest China is the support provided by the rapid development of blasting industry engineering technology in China. In the process of tunnel construction using the drilling and blasting method, in addition to blasting vibration disasters the phenomenon of overbreak and underbreak caused by blasting construction is a prominent problem. This phenomenon not only affects the safety and stability of the tunnel excavation but also seriously increases the construction cost. Based on a short mountain hard rock tunnel project in southwest China, this paper studies the effect of blasting construction on the blasting vibration of adjacent structures and the influence of tunnel contour forming quality. Through the monitoring and analysis of in situ blasting vibration, the Sadowski formula is used to study the attenuation law of blasting vibration velocity in different tunnel sites, which provides a theoretical basis for tunnel blasting vibration control. This article compares the use of overbreak and underbreak value with the traditional method to determine the degree of overbreak and underbreak. It introduces the analysis of contour section fractal dimension value and uses fractal theory in the Python image processing module to accurately and quantitatively describe the problems of tunnel overbreak and underbreak. The feasibility and accuracy of this method have been verified, by combining the total station and 3D laser scanner results of overbreak and underbreak measurements of the Brenner Base Tunnel and a short hard rock tunnel in a mountainous area of southwestern China. The blasting scheme was optimized from the aspects of cut hole form, detonator interval time, and peripheral hole charge structure, and the rationality of the optimized scheme was verified according to the on-site blasting experiments. It has a profound influence on strengthening the protection of adjacent tunnel structures and improving the economic benefit of mountain highway projects.

Limitations in Tunnel Portal Design: An Evaluation Using Numerical Models and Line Surveys

In this study, engineering geology and geotechnical design studies of a highway tunnel project, located on the route of Zonguldak-Amasra-Kurucasile, was expressed. Owing to the low overburden thickness the subjected slope tunnel, especially the right tube in accordance with the project kilometer incremental direction, will be exposed to asymmetrical load after commence of the excavation. Besides, thicknesses between right tube right wall and the slope face in this section has decreased up to 6 m level. Moreover, as the tunnel is passing under the 1st grade archeological protection area, some of the site investigation studies, such as geotechnical drilling and site laboratory works could not have been performed. Thus, this study is explaining the determination of excavation support system of slope tunnel by using engineering geology studies and numerical models. As the tunnel site is located under the 1st grade archeological protection area, any of the required geotechnical site investigation drilling studies and corresponding site testing was not performed on the tunnel axis. Instead of this, line surveys, local sampling, and internationally accepted rock mass classification studies (RMR, Q, GSI) were performed on the rock mass outcrops, which are positioned against to the Black Sea. At the conclusion of these studies, rock mass engineering properties were determined through the utilization of empirical equations that incorporate data derived from site investigation studies and laboratory test results as input.

Fragment-Based Discovery of Allosteric Inhibitors of SH2 Domain-Containing Protein Tyrosine Phosphatase-2 (SHP2).

The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2. Structure-guided optimization, including several computational methods, led to the discovery of two structurally distinct series of SHP2 inhibitors binding to the previously reported allosteric tunnel binding site (Tunnel Site). One of these series was advanced to a low-nanomolar lead that inhibited tumor growth when dosed orally to mice bearing HCC827 xenografts. Furthermore, a third series of SHP2 inhibitors was discovered binding to a previously unreported site, lying at the interface of the C-terminal SH2 and catalytic domains.

A high resolution detection approach combining probe drilling and horizontal cross-hole resistivity tomography to interpret water conducting channels ahead of the tunnel: A case study in Yunnan, China

The geological conditions in Yunnan Province, China, are intricate, and numerous challenges are anticipated during tunnel excavation. The goal of this study was to develop a high resolution detection approach combining probe drilling and horizontal cross-hole resistivity tomography to interpret water conducting channels ahead of the tunnel. A complex section of the Xianglu Mountain tunnel was taken as an example. Drilling data from 10 boreholes are used to establish the initial resistivity model ahead of the tunnel face. The utilization of drilling data as a priori information refines the horizontal cross-borehole resistivity tomography imaging results, providing a more accurate depiction of the subsurface conditions. In practical applications, the use of multiple boreholes for high resolution detection via probe drilling analysis and horizontal cross-hole resistivity tomography is relatively uncommon in complex underground environments and represents an engineering innovation. At the Xianglu Mountain tunnel site, 13 electrical resistivity tomography (ERT) profiles were executed to thoroughly assess the geological conditions. A 3-D resistivity model was constructed via interpolation of this dataset. The 3-D resistivity model not only facilitated precise estimation of the 3-D hydrogeological environment at the Xianglu Mountain tunnel site but also enhanced the accuracy of identifying the water conducting channels by revealing low-resistivity interconnected zones. This approach offers a precise guide for determining the location of the critical water conducting channels and for optimizing grouting treatment strategies based on the characterization, geometry, resistivity spatial distribution, and hydrogeological conditions of the studied zones. The acquired results, which are in good accordance with the reality of the studied area in terms of locating the water conducting channels, can be utilized to develop preventative techniques for water and mud inrush disasters during tunnel construction.

Risk prediction of water inrush in karst tunnels and analysis of surrounding rock stability

Karst tunnel construction has always been an important and difficult point in tunnel engineering. Based on the Yilai Expressway Wantan Tunnel Project, this paper analyzes the water-bearing lithofacies of the surrounding rock of the Wantan Tunnel and the karst hydrogeological conditions of the tunnel site area, and predicts the risk of tunnel water inrush disaster. Through monitoring and measurement, the existing construction technology was analyzed and the following conclusions were drawn: The surrounding rock of the Wantan Tunnel is a typical carbonate phase stratum, with a large amount of water inflow during the rainy season. There are local caves and karst pipes, and the comprehensive water inrush assessment level is III (medium risk); According to the monitoring, the displacement and deformation of each monitoring section in the tunnel changes normally, and the cumulative deformation value is less than 1/3 of the limit value. The stability of the surrounding rock is good, and the construction safety is high.

Realistic long-term stress levels in a deep segmented tunnel lining, from hereditary mechanics-informed evaluation of strain measurements

Realistic estimation of stresses in segmented tunnel linings is a challenge tackled herein by means of a hybrid, i.e. computational-experimental, approach. Thermistor-equipped vibrating wire strain gauges were installed (i) into concrete samples undergoing one year-long uniaxial creep tests under the environmental conditions of the tunnel site, and (ii) into the tubbings making up the tunnel lining of the Koralm tunnel. The data obtained from the creep tests allow for calibration and validation of an integro-differential thermo-viscoelastic model. The creep function combines a power-law for short-term creep with a logarithmic law for long-term creep. The corresponding relaxation function is determined by means of Laplace-Carson transformation, inversion, and back-transformation. This is the basis for translating the circumferential strain histories measured in the tubbings of Ring 2013 in Koralm tunnel KAT3 into circumferential and longitudinal stress evolutions. They are mainly due to mechanical ground-shell interactions. The corresponding degree of utilization increases during the first four months after ring installation, and remains virtually constant thereafter. Stress fluctuations due to seasonal temperature variations play only a minor role. With regards to a long-term prognosis, it is very interesting to note that the strain measurements recorded in the tubbings, when plotted as function of the logarithm of time, follow bi-linear trends. These trends can be extrapolated to 150 years, the targeted service life of newly built tunnels in Austria. Throughout this period, the viscoelasticity-based estimates of the stresses in the vicinity of the strain sensors stay temporally constant, at some 40% of the strength of concrete.

Experimental analysis of low-dip reverse fault dislocation effects on tunnel site models with different soil properties

The fortification system of the tunnel structure spanning the active fault, such as the failure mechanism and fault-resistant design (measures), has not been thoroughly established. In this study, the self-developed cross-fault large-scale bedrock dislocation loading device platform is utilized to carry out the model test of the tunnel structure and soil site of sand and cohesive soil when the low-angle reverse fault dislocation occurs, based on the earthquake damage. The results demonstrate that: (1) When the fault is staggered, the segmented flexible joint tunnel segment is more favorable in the cohesive soil site. (2) When compared to the cohesive soil tunnel structure site, the strain change of the tunnel structure in the sandy soil site is greater, with the vault increasing by roughly two times and the arch bottom increasing by nearly six times. After the tunnel is buried, the uplift range of the sand cover layer grows, revealing uneven deformation, and the rupture zone migrates to the footwall; hence, the sand site plays a “add seismic” role in the cross-fault tunnel structure. (3) Knowing the location and shape of the rupture range of the overburden soil caused by bedrock dislocation under different inclination angles and soil properties is required in the design in order to place the buried depth and segment length of the tunnel reasonably and take fault-resistant measures.

Investigation of hydrogeology condition in Manikin Dam Diversion Tunnel, Timor Island, Indonesia: A Case Study

The seepages phenomenon happened in the construction site of the Manikin Dam Diversion Tunnel, Timor Island, Indonesia, has hampered the progress of construction. It seems impossible since the tunnel construction site was at the Bobonaro Complex. This condition leads to an investigate the possibility of another seepage occurrence along the tunnel construction site since more than 500 m long tunnel remains to be excavated. This study was conducted by direct observation method of the geological and hydrogeological conditions. Interpretation to direct field of geological mapping result, 10 borehole cutting samples, 6 lines of geo-electrical survey data, and face-mapping of tunnel excavation data resulting the surface and subsurface geological conditions. Hydrogeological mapping was performed to portray groundwater conditions at the tunnel site. The research reveals that the study area consists of scaly clay (fragmented with exotic block) and carbonate sandstone units. The scaly clay is impermeable, while the carbonate sandstone is permeable, but the fractured exotic blocks also act as an aquifer. The groundwater flows to the tunnel comes from this fractured zone in the exotic blocks. Based on this condition, other seepage phenomena could happen, as shown in the interpretation of the geo-electrical survey.

Experimental and Numerical Study of Soil Strata for Underground Transportation System: A Case Study

In the current capital of Yemen, Sana’a, a time-efficient and economical transportation system is one of the greatest challenges to overcome the increasing urbanization for many years. Rapid transport systems use tunnel structures to reach the city's most inaccessible areas. Given the Gulf's geopolitical unrest, these structures could also serve as emergency shelters. Consequently, this research conducted an experimental soil exploration investigation in Sana'a, Yemen, to identify potential tunneling sites for the city's rapid transit system. The field exploration, in-situ, and laboratory soil testing at the four locations were performed with the collaboration of the Ministry of Public Works & Highways, Yemen. Further, to calculate the geotechnical parameters for tunnel design, numerical analysis has been carried out using the finite element package ABAQUS, and two-dimensional plane-strain numerical models of underground tunnel structure have been developed to conduct the parametric study in different soil types and boundary conditions under static loading. The material behavior of soil strata has been incorporated into the well-known Mohr-Coulomb constitutive model. The field investigation found that the geotechnical properties of the soil strata in Sana’a have a lot of variation. The numerical study shows that the maximum deformation in the concrete liner of the tunnel was observed at the crown of the tunnel. The ovalling effect in tunnel concrete liner was also seen in all the tunnel models, and the maximum ground settlement at sites 1, 2, 3, and 4 was estimated to be approximately 4, 25, 17, and 11 mm, respectively. Doi: 10.28991/CEJ-2024-010-01-03 Full Text: PDF

Use of Electrocautery to Facilitate Suture Passage Through the Greater Trochanter of the Femur: A Biomechanical Study.

The specific aims of this study were to evaluate (1) the axial force reduction of suture passage utilizing electrocautery when applied to the greater trochanter of the femur, (2) the temperature change caused while using electrocautery for suture passage, and (3) the failure loads and failure modes utilizing this technique. Five matched pairs of fresh-frozen femurs were used and classified into two groups: with electrocautery on needle (study group) and without electrocautery on needle (control group). Two bicortical, osseous tunnels were made around the insertion of the gluteus medius tendon. Each specimen was sequentially tested in a needle penetration test and a single load-to-failure test. A #5 Ethibond suture with a straight needle was used. Electrocautery reduced the peak axial force for bone penetration in 40% (near cortex) and 70% (far cortex) of the trials, and no significant difference was detected between groups or between two osseous tunnels. The average peak force was significantly higher for the far cortex for both groups and for both osseous tunnels compared to the near cortex. There was no significant change in temperature of the tunnel site with electrocautery. Ninety percent of the samples experienced bone tunnel failure for the study group compared to 70% in the control group. The average ultimate failure load for the study group was lower compared with the control group, but this finding was not statistically significant (range: 6%-15%). Suture passage using electrocautery may not significantly decrease the peak force needed to pass a needle directly through the greater trochanter.

Engineering geology for site characterization in Tunnel 2 Bintang Bano irrigation area, West Sumbawa, West Nusa Tenggara Province

Site characteristics develop a better understanding of geological conditions to prevent tunnel failure. Tunnel 2 Bintang Bano Irrigation Area in Seloto, West Sumbawa, West Nusa Tenggara Province, was designed with different interpretations of geological conditions that could lead to inaccuracy of the tunnel design. This paper aims to identify the characteristics of the tunnel site area through engineering geology, including morphological and lithological unit, geological structure, and geomechanics, which are rock mass characterization using Rock Mass Rating (RMR) and Tunnelling Quality Index (Q-system), for the excavation planning area. This area is identified as volcanic landforms categorized as lava ridges with steep slopes and alluvial plains with very sloping slopes. The lithologies are altered andesite and gravelly sand unit. Altered andesite with tuff intercalation was found in the subsurface. The tunnel is projected to be excavated in rock mass with dominantly fair rock with ratings (±40≤RMR≤65/±4.33≤Q-System≤8.67) approximately 60% of the excavation area, ±30% area of good rock (63≤RMR≤69/10.67≤Q-system≤11.40) and 10% poor rock (26≤RMR≤40/1≤Q-system≤3.57).

Seismic Load Design of Rukoh Dam Suppletion Tunnel in Pidie Regency, Aceh, Indonesia, Based on Deterministic and Probabilistic Seismic Hazard Analyses

The Rukoh Dam suppletion tunnel construction site in Pidie Regency, Aceh province, is located 5.6 kilometers from the Seulimeum-South segment of the active Sumatran fault. The active fault features a strike-slip fault mechanism with a slip rate of 7.0 millimeters per year and a maximum earthquake-recorded magnitude of 6.9 Mw. Considering that the construction site is located less than 10 kilometers from the active fault, which may cause earthquakes with a magnitude of at least 6 Mw, the SNI 1729:2019, which describes the procedures for planning earthquake resistance for buildings and non-building structures, requires the seismic load to be designed based on the site-specific responses analysis. Determination of the seismic load using a deterministic seismic hazard analysis was the objective of this study. The seismic load based on the probabilistic seismic hazard analysis by Pusat Studi Gempa Nasional (PusGen) in 2017 is also compared. The 2017 Indonesian Earthquake Source and Hazard Map were used to find out about the fault mechanism, slip rate, deterministic magnitude, orientation, and coordinates of traces. The deterministic seismic hazard analysis was conducted using EZ-FRISK 8.07 software and attenuation equations with shallow crustal earthquake sources for fault and shallow background earthquake sources, i.e., the Boore-Atkinson NGA 2014, the Campbell-Bozorgnia NGA 2014, and the Chiou-Youngs NGA 2014 equations. The deterministic analysis based on those attenuation equations predicted the active fault to result in a peak ground acceleration (PGA) value of 0.66 g at the construction site of the Rukoh Dam suppletion tunnel. In comparison, the probabilistic hazard analysis conducted by Pusat Studi Gempa Nasional (PusGen) in 2017 indicated a peak ground acceleration (PGA) of 0.537 g. Therefore, the seismic load is recommended for the structural designs of the embankment dam and the other infrastructures, particularly the suppletion tunnel.