Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
Evaluating the Impact of Secant Piles on Retaining Wall Safety at Lapangan Merdeka Medan Author:
Adinda Juwita Nasution1 Rahmatsyah Fadlan2 Habib Berutu3 Afiliation:
Universitas Al-Azhar Medan1,2,3 Corresponding email Histori Naskah:
Submit: 2025-08-21 Accepted: 2025-11-13 Published: 2025-11-15 This is an Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.
International License Abstract:
This study investigates the effectiveness of integrating secant piles into retaining wall systems for basement construction, with a specific focus on the Medan Merdeka Square Revitalization Project.
As part of a major redevelopment effort in a historically significant urban area, ensuring the structural stability of basement walls is essential to protect both the site and surrounding infrastructure.
Secant pile walls, composed of overlapping reinforced concrete piles, offer enhanced lateral resistance and groundwater control compared to conventional retaining structures.
The research evaluates wall performance before and after the application of secant piles through geotechnical analysis and engineering stability assessments.
The methodology includes determining lateral earth pressure using RankineAos Theory and conducting stability checks against overturning, sliding, and bearing capacity failure.
Soil characteristics, earth pressure coefficients, and relevant safety factors are analyzed to understand how the combined secant pileAereinforced concrete system distributes loads and improves structural Construction methods and sequencing are also considered to ensure minimal disruption to the heritage environment.
The results indicate that the retaining wall with added secant piles meets all required stability criteria: sliding resistance is safe, overturning potential is negligible, and bearing capacity is adequate to support the applied loads.
Additionally, the recorded deflection value of 0.
8 remains within acceptable limits, confirming the structural suitability of the design.
Overall, the incorporation of secant piles significantly enhances the stability and reliability of the basement retaining wall, making it appropriate for long-term implementation in the revitalization project.
Keywords: Basement Construction.
Lapangan Merdeka Medan.
Retaining Wall.
Secant Pile.
Stability Analysis Introduction The revitalization project of Lapangan Merdeka Medan includes the construction of a public square, supporting facilities, and a basement.
In addition to being a historical site, the revitalization is also aimed at developing green open space.
According to the design plan, the revitalized area will feature a public stage and supporting infrastructure, incorporating the concept of preserving historical urban spaces with a contemporary design approach.
This revitalization effort has gained significant support from various segments of the community.
The stability of the retaining wall structure in the Lapangan Merdeka Medan revitalization project is a critical aspect, as soil bearing capacity plays a fundamental role in the performance of building foundations.
Therefore, the use of a retaining wall system combining secant pile and reinforced concrete walls is considered a suitable solution for this project.
Secant pile walls function as rigid lateral support structures for excavations and underground facilities, constructed through a series of overlapping concrete piles that Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
create a continuous barrier against soil and water infiltration.
Recent experimental investigations (Basha et , 2.
have demonstrated that secant pile walls possess both structural and overall stability characteristics necessary to withstand lateral earth pressures as well as applied axial loads, making them particularly suitable for urban construction projects with space limitations.
Advanced monitoring technologies using distributed fiber optic sensors have proven effective in tracking the behavior of secant pile walls during construction and excavation phases (Zhang et al.
, 2.
, with studies showing minimal lateral displacement after excavation due to the high stiffness of properly designed secant pile walls.
Furthermore, comprehensive investigations of deep excavations in layered stiff ground conditions (Christensen et al.
, 2.
have revealed that ground stiffness emerges as the critical factor affecting wall deflections during both cantilever and supported construction stages, emphasizing the importance of thorough geotechnical investigation prior to design.
The application of secant pile technology has gained considerable traction in urban construction due to its versatility and effectiveness in controlling both earth retention and groundwater.
Secant pile walls can be constructed in various soil conditions, including challenging terrains with cobbles and boulders, and can be supported by anchor or strutting systems with waler beams to distribute loads and prevent structural failure.
Recent parametric studies (Gowthaman & Anburaj, 2.
have also examined the performance of permanently anchored secant pile walls under earthquake loading conditions, providing valuable insights for seismic design considerations in urban areas.
In various cases involving the use of secant piles in the city of Medan, notable examples include the implementation of secondary secant pile techniques as retaining walls in the construction of a pump house for the wastewater pipeline network optimization project and the analysis of retaining wall stability in the pump house construction project on Jl.
Sidorukun.
Pulo Brayan Darat.
Medan.
These local applications demonstrate the growing confidence in secant pile technology for critical infrastructure projects in the region, providing valuable precedents for the Lapangan Merdeka revitalization project.
Literature Review Basha et al.
- Performance Analysis of Axially Loaded Secant Pile Wall Penelitian yang dilakukan oleh Basha et al.
mengkaji kinerja dinding secant pile yang dibebani secara aksial melalui pendekatan eksperimental pada tanah pasir.
Studi ini menggunakan model skala laboratorium untuk menganalisis perilaku struktural dan stabilitas keseluruhan dari dinding secant pile ketika mengalami beban aksial dan tekanan lateral tanah secara bersamaan.
Hasil penelitian menunjukkan bahwa dinding secant pile memiliki kapasitas daya dukung yang signifikan dan mampu mempertahankan stabilitasnya bahkan di bawah kondisi pembebanan kombinasi.
Penelitian ini juga mengidentifikasi pola distribusi tegangan pada pile dan mekanisme transfer beban ke tanah di sekitarnya.
Temuan ini memberikan kontribusi penting dalam memahami perilaku struktural secant pile, khususnya untuk aplikasi pada proyek konstruksi perkotaan dengan keterbatasan ruang.
Relevansi penelitian ini terhadap proyek Lapangan Merdeka Medan terletak pada validasi kemampuan sistem secant pile dalam menahan beban vertikal dari struktur di atasnya sekaligus berfungsi sebagai dinding penahan tanah, yang merupakan kondisi serupa dengan kebutuhan proyek revitalisasi yang melibatkan konstruksi basement dan fasilitas pendukung.
Zhang et al.
- Monitoring Excavation-Induced Deformation Using Distributed Fiber Optic Sensors Zhang et al.
melakukan penelitian tentang pemantauan deformasi dinding secant pile akibat galian menggunakan sensor serat optik terdistribusi .
istributed fiber optic sensor.
Penelitian ini mengaplikasikan teknologi monitoring canggih untuk melacak pergerakan dan deformasi dinding secant pile secara real-time selama proses konstruksi dan penggalian.
Hasil monitoring menunjukkan bahwa Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
dinding secant pile yang dirancang dengan baik mengalami perpindahan lateral yang minimal setelah penggalian, yang mengindikasikan kekakuan struktural yang tinggi.
Studi ini juga berhasil mengidentifikasi zona kritis pada dinding yang mengalami tegangan maksimum, sehingga memungkinkan intervensi dini jika terjadi kondisi yang tidak diinginkan.
Penggunaan teknologi fiber optic sensors memberikan data kontinu dan akurat sepanjang kedalaman dinding, yang tidak dapat dicapai dengan metode monitoring Penelitian ini sangat relevan untuk proyek Lapangan Merdeka Medan karena menekankan pentingnya monitoring real-time untuk memastikan keamanan struktur penahan tanah, terutama mengingat lokasi proyek yang berada di area urban dengan tingkat aktivitas tinggi dan berdekatan dengan bangunan bersejarah yang harus dilindungi dari potensi settlement atau pergerakan tanah.
Christensen et al.
- Deformation Behaviour in Layered Soil-Rock Profiles Christensen et al.
menginvestigasi perilaku deformasi dinding secant pile pada profil tanah berlapis yang terdiri dari kombinasi tanah dan batuan di Copenhagen.
Penelitian ini menganalisis data dari beberapa proyek galian dalam .
eep excavatio.
untuk memahami faktor-faktor yang mempengaruhi defleksi dinding selama tahap konstruksi kantilever maupun tahap dengan sistem penyangga.
Temuan utama penelitian menunjukkan bahwa kekakuan tanah .
round stiffnes.
merupakan faktor kritis yang paling berpengaruh terhadap besarnya defleksi dinding, lebih signifikan dibandingkan faktor-faktor lain seperti panjang kantilever atau kedalaman galian.
Studi ini juga mengungkapkan bahwa pada kondisi tanah berlapis dengan variasi kekakuan yang tinggi, diperlukan pemodelan yang lebih detail untuk memprediksi perilaku dinding secara akurat.
Penelitian ini memberikan pelajaran penting tentang pentingnya investigasi geoteknik yang menyeluruh sebelum tahap desain, termasuk karakterisasi detail dari setiap lapisan tanah.
Untuk proyek Lapangan Merdeka Medan, penelitian ini sangat relevan mengingat kondisi tanah di kota Medan yang umumnya bersifat heterogen dengan variasi jenis dan karakteristik tanah pada kedalaman yang berbeda, sehingga memerlukan perhatian khusus dalam desain dinding penahan tanah untuk mengantisipasi potensi deformasi yang dapat mempengaruhi keamanan struktur.
Research Method This study employs a quantitative evaluative approach aimed at analyzing and comparing the safety factors of retaining wall structures before and after the installation of secant piles, utilizing geotechnical data obtained from field investigations.
The analysis focuses on soil lateral pressure, slope stability, and structural deflection to assess the effectiveness of secant pile implementation in enhancing the safety and performance of the retaining wall system.
Primary data, such as SPT and CPT test results, were unavailable due to time constraints and limited access to the project site.
Therefore, this study relies on secondary data sourced from official planning reports of the Lapangan Merdeka Medan revitalization project prepared by the consulting engineers.
This study did not employ geotechnical software validation due to the following reasons the research focused on manual theoretical calculations, applying conventional theoretical methods such as RankineAos theory and traditional stability equations, without the use of numerical modeling software.
In addition, limited access to commercial geotechnical software licenses restricted the ability to conduct numerical validation within the scope of this study.
Furthermore, due to time and resource constraints, software-based validation was not carried out and is recommended to be addressed in future research.
Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
Figure 1 Research Flow Chart This study relies exclusively on secondary data, which were obtained from documents and technical reports provided by the project stakeholders involved in the Revitalization of Lapangan Merdeka Medan.
The data A Standard Penetration Test (SPT) and Cone Penetration Test (CPT) results.
A Drilling logs from soil investigation A Technical drawings .
hop drawing.
of the retaining wall structure.
A Soil parameter reports, such as cohesion, internal friction angle, and unit weight.
A Literature and technical references, including Indonesian National Standards (SNI), geotechnical engineering textbooks, and previous studies related to earth pressure and secant pile applications.
Techniques of Data Collection A Document Review Collection of geotechnical data and technical reports from the Revitalization Project of Lapangan Merdeka Medan.
The documents include Standard Penetration Test (SPT) results.
Cone Penetration Test (CPT) data, drilling logs, soil parameter reports, and technical drawings related to the retaining wall and basement structure.
A Drawing Analysis Analysis of structural shop drawings and reinforcement details to understand the geometry, structural elements, and construction methods used in both the original retaining wall and the configuration after the addition of secant piles.
A Literature Study Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
Use of theoretical references, calculation standards, and design guidelines obtained from textbooks, scientific journals, and national regulations such as SNI.
These references support the analysis of lateral earth pressure, wall deflection, and safety factor calculations.
Steps in Data Analysis:
Identification of Structural and Soil Parameters: Determine the geotechnical and structural parameters necessary for the analysis, including soil cohesion, internal friction angle, and unit These parameters are derived from SPT and CPT data, as well as structural dimensions from shop drawings.
Safety Factor Calculation Calculate the safety factor of the retaining wall against three failure modes:
Sliding, based on the balance of horizontal forces.
Overturning, based on moment equilibrium.
Bearing capacity, based on soil pressure and allowable bearing stress Lateral Earth Pressure and Deflection Analysis Analyze lateral earth pressure using RankineAos Theory to determine the magnitude of force acting on the wall.
Calculate the resulting wall deflection using appropriate structural beam theory to ensure the deformation remains within allowable limits.
Comparative Evaluation Before and After Secant Pile Installation Evaluate and compare all safety factor values and deflection results between two conditions:
Before the application of secant pile .
riginal conditio.
After the application of secant .
mproved conditio.
The comparison aims to assess the improvement in structural performance and determine the effectiveness of secant pile Result Based on the site investigation, drilling log data indicated five distinct soil layers:
Sandy clay with medium to stiff consistency Silty fine sand and calcareous fine sand with medium density Medium sand with pumice, classified as dense to very dense Dense medium sand and Dense fine sand.
Cone Penetration Testing (CPT) was performed following ASTM D3411 T75 using a 2.
5-ton light-duty cone penetrometer.
The test measured cone tip resistance .
hear force per unit are.
and sleeve adhesion .
hear force per unit lengt.
Testing continued until reaching either hard soil (CR Ou 150 kg/cmA) or a depth of 20 meters.
When CPT data alone was insufficient for soil classification, nearby borehole data was used as a reference.
Elektriese: Jurnal Sains dan Teknologi Elektro Volume 15.
Number 02.
Oktober 2025 e-ISSN: 2830-3512X https://doi.
org/10.
47709/elektriese.
During the test, as the bicone penetrated into the soil, measurements were taken for both Cone Resistance (CR) and Total Resistance (TR) at 20 cm intervals, using a manometer.
Based on the obtained CR and TR values, further analysis was conducted to derive soil strength parameters and interpret subsurface The retaining wall design in the Revitalization Project of Lapangan Merdeka Medan initially followed a basic stability approach, where structural reinforcement was only considered after early signs of potential failure, such as excessive deflection or low safety factor values.
As a result, no advanced soil-structure interaction method or preventive reinforcement, such as secant pile, was implemented in the initial design Improvements were introduced only after the structural performance was reevaluated and found to be close to minimum safety thresholds.
FR = TR Ae CR FR (Friction Resistanc.
= 5 kg/cmA TR (Total Resistanc.
= 231 kg/cmA CR (Cone Resistanc.
= 226 kg/cmA SF = FR x 20/10 .
g/c.
SF (Skin Frictio.
= 10 kg/cm 20 = Reading interval .
10 = Equipment factor (Reduction Facto.
TSF (Total Skin Frictio.
= 714 kg/cm LSF = FR / 10 LSF (Local Skin Frictio.
= 0.
50 kg/cmA Discussion